cppreference.com

Assignment operators.

Assignment and compound assignment operators are binary operators that modify the variable to their left using the value to their right.

[ edit ] Simple assignment

The simple assignment operator expressions have the form

Assignment performs implicit conversion from the value of rhs to the type of lhs and then replaces the value in the object designated by lhs with the converted value of rhs .

Assignment also returns the same value as what was stored in lhs (so that expressions such as a = b = c are possible). The value category of the assignment operator is non-lvalue (so that expressions such as ( a = b ) = c are invalid).

rhs and lhs must satisfy one of the following:

  • both lhs and rhs have compatible struct or union type, or..
  • rhs must be implicitly convertible to lhs , which implies
  • both lhs and rhs have arithmetic types , in which case lhs may be volatile -qualified or atomic (since C11)
  • both lhs and rhs have pointer to compatible (ignoring qualifiers) types, or one of the pointers is a pointer to void, and the conversion would not add qualifiers to the pointed-to type. lhs may be volatile or restrict (since C99) -qualified or atomic (since C11) .
  • lhs is a (possibly qualified or atomic (since C11) ) pointer and rhs is a null pointer constant such as NULL or a nullptr_t value (since C23)

[ edit ] Notes

If rhs and lhs overlap in memory (e.g. they are members of the same union), the behavior is undefined unless the overlap is exact and the types are compatible .

Although arrays are not assignable, an array wrapped in a struct is assignable to another object of the same (or compatible) struct type.

The side effect of updating lhs is sequenced after the value computations, but not the side effects of lhs and rhs themselves and the evaluations of the operands are, as usual, unsequenced relative to each other (so the expressions such as i = ++ i ; are undefined)

Assignment strips extra range and precision from floating-point expressions (see FLT_EVAL_METHOD ).

In C++, assignment operators are lvalue expressions, not so in C.

[ edit ] Compound assignment

The compound assignment operator expressions have the form

The expression lhs @= rhs is exactly the same as lhs = lhs @ ( rhs ) , except that lhs is evaluated only once.

[ edit ] References

  • C17 standard (ISO/IEC 9899:2018):
  • 6.5.16 Assignment operators (p: 72-73)
  • C11 standard (ISO/IEC 9899:2011):
  • 6.5.16 Assignment operators (p: 101-104)
  • C99 standard (ISO/IEC 9899:1999):
  • 6.5.16 Assignment operators (p: 91-93)
  • C89/C90 standard (ISO/IEC 9899:1990):
  • 3.3.16 Assignment operators

[ edit ] See Also

Operator precedence

[ edit ] See also

  • Recent changes
  • Offline version
  • What links here
  • Related changes
  • Upload file
  • Special pages
  • Printable version
  • Permanent link
  • Page information
  • In other languages
  • This page was last modified on 19 August 2022, at 08:36.
  • This page has been accessed 54,567 times.
  • Privacy policy
  • About cppreference.com
  • Disclaimers

Powered by MediaWiki

CProgramming Tutorial

  • C Programming Tutorial
  • C - Overview
  • C - Features
  • C - History
  • C - Environment Setup
  • C - Program Structure
  • C - Hello World
  • C - Compilation Process
  • C - Comments
  • C - Keywords
  • C - Identifiers
  • C - User Input
  • C - Basic Syntax
  • C - Data Types
  • C - Variables
  • C - Integer Promotions
  • C - Type Conversion
  • C - Constants
  • C - Literals
  • C - Escape sequences
  • C - Format Specifiers
  • C - Storage Classes
  • C - Operators
  • C - Decision Making
  • C - While loop
  • C - Functions
  • C - Scope Rules
  • C - Pointers
  • C - Strings
  • C - Structures
  • C - Bit Fields
  • C - Typedef
  • C - Input & Output
  • C - File I/O
  • C - Preprocessors
  • C - Header Files
  • C - Type Casting
  • C - Error Handling
  • C - Recursion
  • C - Variable Arguments
  • C - Memory Management
  • C - Command Line Arguments
  • C Programming Resources
  • C - Questions & Answers
  • C - Quick Guide
  • C - Useful Resources
  • C - Discussion
  • Selected Reading
  • UPSC IAS Exams Notes
  • Developer's Best Practices
  • Questions and Answers
  • Effective Resume Writing
  • HR Interview Questions
  • Computer Glossary

Assignment Operators in C

In C, the assignment operator stores a certain value in an already declared variable. A variable in C can be assigned the value in the form of a literal, another variable or an expression. The value to be assigned forms the right hand operand, whereas the variable to be assigned should be the operand to the left of = symbol, which is defined as a simple assignment operator in C. In addition, C has several augmented assignment operators.

The following table lists the assignment operators supported by the C language −

Simple assignment operator (=)

The = operator is the most frequently used operator in C. As per ANSI C standard, all the variables must be declared in the beginning. Variable declaration after the first processing statement is not allowed. You can declare a variable to be assigned a value later in the code, or you can initialize it at the time of declaration.

You can use a literal, another variable or an expression in the assignment statement.

Once a variable of a certain type is declared, it cannot be assigned a value of any other type. In such a case the C compiler reports a type mismatch error.

In C, the expressions that refer to a memory location are called "lvalue" expressions. A lvalue may appear as either the left-hand or right-hand side of an assignment.

On the other hand, the term rvalue refers to a data value that is stored at some address in memory. A rvalue is an expression that cannot have a value assigned to it which means an rvalue may appear on the right-hand side but not on the left-hand side of an assignment.

Variables are lvalues and so they may appear on the left-hand side of an assignment. Numeric literals are rvalues and so they may not be assigned and cannot appear on the left-hand side. Take a look at the following valid and invalid statements −

Augmented assignment operators

In addition to the = operator, C allows you to combine arithmetic and bitwise operators with the = symbol to form augmented or compound assignment operator. The augmented operators offer a convenient shortcut for combining arithmetic or bitwise operation with assignment.

For example, the expression a+=b has the same effect of performing a+b first and then assigning the result back to the variable a.

Similarly, the expression a<<=b has the same effect of performing a<<b first and then assigning the result back to the variable a.

Here is a C program that demonstrates the use of assignment operators in C:

When you compile and execute the above program, it produces the following result −

  • C++ Language
  • Ascii Codes
  • Boolean Operations
  • Numerical Bases

Introduction

Basics of c++.

  • Structure of a program
  • Variables and types
  • Basic Input/Output

Program structure

  • Statements and flow control
  • Overloads and templates
  • Name visibility

Compound data types

  • Character sequences
  • Dynamic memory
  • Data structures
  • Other data types
  • Classes (I)
  • Classes (II)
  • Special members
  • Friendship and inheritance
  • Polymorphism

Other language features

  • Type conversions
  • Preprocessor directives

Standard library

  • Input/output with files

Assignment operator (=)

Arithmetic operators ( +, -, *, /, % ), compound assignment (+=, -=, *=, /=, %=, >>=, <<=, &=, ^=, |=), increment and decrement (++, --), relational and comparison operators ( ==, =, >, <, >=, <= ), logical operators ( , &&, || ), conditional ternary operator ( ), comma operator ( , ), bitwise operators ( &, |, ^, ~, <<, >> ), explicit type casting operator, other operators, precedence of operators.

C++ Tutorial

C++ functions, c++ classes, c++ examples, c++ assignment operators, assignment operators.

Assignment operators are used to assign values to variables.

In the example below, we use the assignment operator ( = ) to assign the value 10 to a variable called x :

The addition assignment operator ( += ) adds a value to a variable:

A list of all assignment operators:

Get Certified

COLOR PICKER

colorpicker

Report Error

If you want to report an error, or if you want to make a suggestion, do not hesitate to send us an e-mail:

[email protected]

Top Tutorials

Top references, top examples, get certified.

This browser is no longer supported.

Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.

about_Assignment_Operators

  • 2 contributors

Short description

Describes how to use operators to assign values to variables.

Long description

Assignment operators assign one or more values to a variable. The equals sign ( = ) is the PowerShell assignment operator. PowerShell also has the following compound assignment operators: += , -= , *= , %= , ++ , -- , ??= . Compound assignment operators perform operations on the values before the assignment.

The syntax of the assignment operators is as follows:

  • <assignable-expression> <assignment-operator> <value>

Assignable expressions include variables and properties. The value can be a single value, an array of values, or a command, expression, or statement.

The increment and decrement operators are unary operators. Each has prefix and postfix versions.

  • <assignable-expression><operator>
  • <operator><assignable-expression>

The value of the assignable expression must be a number or it must be convertible to a number.

Using the assignment operator

Variables are named memory spaces that store values. You store the values in variables using the assignment operator = . The new value can replace the existing value of the variable, or you can append a new value to the existing value. For example, the following statement assigns the value PowerShell to the $MyShell variable:

When you assign a value to a variable in PowerShell, the variable is created if it didn't already exist. For example, the first of the following two assignment statements creates the $a variable and assigns a value of 6 to $a . The second assignment statement assigns a value of 12 to $a . The first statement creates a new variable. The second statement changes only its value:

Variables in PowerShell don't have a specific data type unless you cast them. When a variable contains only one object, the variable takes the data type of that object. When a variable contains a collection of objects, the variable has the System.Object data type. Therefore, you can assign any type of object to the collection. The following example shows that you can add process objects, service objects, strings, and integers to a variable without generating an error:

Because the assignment operator = has a lower precedence than the pipeline operator | , parentheses aren't required to assign the result of a command pipeline to a variable. For example, the following command sorts the services on the computer and then assigns the sorted services to the $a variable:

You can also assign the value created by a statement to a variable, as in the following example:

This example assigns zero to the $a variable if the value of $b is less than zero. It assigns the value of $b to $a if the value of $b isn't less than zero.

To assign an array (multiple values) to a variable, separate the values with commas, as follows:

To assign a hash table to a variable, use the standard hash table notation in PowerShell. Type an at sign @ followed by key/value pairs that are separated by semicolons ; and enclosed in braces { } . For example, to assign a hashtable to the $a variable, type:

To assign hexadecimal values to a variable, precede the value with 0x . PowerShell converts the hexadecimal value (0x10) to a decimal value (in this case, 16) and assigns that value to the $a variable. For example, to assign a value of 0x10 to the $a variable, type:

To assign an exponential value to a variable, type the root number, the letter e , and a number that represents a multiple of 10. For example, to assign a value of 3.1415 to the power of 1,000 to the $a variable, type:

PowerShell can also convert kilobytes KB , megabytes MB , and gigabytes GB into bytes. For example, to assign a value of 10 kilobytes to the $a variable, type:

Using compound assignment operators

Compound assignment operators perform numeric operations on the values before the assignment.

Compound assignment operators don't use dynamic scoping. The variable is always in the current scope.

In the following example, the variable $x is defined in the global scope. The braces create a new scope. The variable $x inside the braces is a new instance and not a copy of the global variable.

When you use the regular assignment operator, you get a copy of the variable from the parent scope. But notice that $x in the parent scope is not changed.

The assignment by addition operator

The assignment by addition operator += either increments the value of a variable or appends the specified value to the existing value. The action depends on whether the variable has a numeric or string type and whether the variable contains a single value (a scalar) or multiple values (a collection).

The += operator combines two operations. First, it adds, and then it assigns. Therefore, the following statements are equivalent:

When the variable contains a single numeric value, the += operator increments the existing value by the amount on the right side of the operator. Then, the operator assigns the resulting value to the variable. The following example shows how to use the += operator to increase the value of a variable:

When the value of the variable is a string, the value on the right side of the operator is appended to the string, as follows:

When the value of the variable is an array, the += operator appends the values on the right side of the operator to the array. Unless the array is explicitly typed by casting, you can append any type of value to the array, as follows:

When the value of a variable is a hash table, the += operator appends the value on the right side of the operator to the hash table. However, because the only type that you can add to a hash table is another hash table, all other assignments fail.

For example, the following command assigns a hash table to the $a variable. Then, it uses the += operator to append another hash table to the existing hash table, effectively adding a new key-value pair to the existing hash table. This command succeeds, as shown in the output:

The following command attempts to append an integer "1" to the hash table in the $a variable. This command fails:

The assignment by subtraction operator

The assignment by subtraction operator -= decrements the value of a variable by the value that's specified on the right side of the operator. This operator can't be used with string variables, and it can't be used to remove an element from a collection.

The -= operator combines two operations. First, it subtracts, and then it assigns. Therefore, the following statements are equivalent:

The following example shows how to use of the -= operator to decrease the value of a variable:

You can also use the -= assignment operator to decrease the value of a member of a numeric array. To do this, specify the index of the array element that you want to change. In the following example, the value of the third element of an array (element 2) is decreased by 1:

You can't use the -= operator to delete the values of a variable. To delete all the values that are assigned to a variable, use the Clear-Item or Clear-Variable cmdlets to assign a value of $null or "" to the variable.

To delete a particular value from an array, use array notation to assign a value of $null to the particular item. For example, the following statement deletes the second value (index position 1) from an array:

To delete a variable, use the Remove-Variable cmdlet. This method is useful when the variable is explicitly cast to a particular data type, and you want an untyped variable. The following command deletes the $a variable:

The assignment by multiplication operator

The assignment by multiplication operator *= multiplies a numeric value or appends the specified number of copies of the string value of a variable.

When a variable contains a single numeric value, that value is multiplied by the value on the right side of the operator. For example, the following example shows how to use the *= operator to multiply the value of a variable:

In this case, the *= operator combines two operations. First, it multiplies, and then it assigns. Therefore, the following statements are equivalent:

When a variable contains a string value, PowerShell appends the specified number of strings to the value, as follows:

To multiply an element of an array, use an index to identify the element that you want to multiply. For example, the following command multiplies the first element in the array (index position 0) by 2:

The assignment by division operator

The assignment by division operator /= divides a numeric value by the value that's specified on the right side of the operator. The operator can't be used with string variables.

The /= operator combines two operations. First, it divides, and then it assigns. Therefore, the following two statements are equivalent:

For example, the following command uses the /= operator to divide the value of a variable:

To divide an element of an array, use an index to identify the element that you want to change. For example, the following command divides the second element in the array (index position 1) by 2:

The assignment by modulus operator

The assignment by modulus operator %= divides the value of a variable by the value on the right side of the operator. Then, the %= operator assigns the remainder (known as the modulus) to the variable. You can use this operator only when a variable contains a single numeric value. You can't use this operator when a variable contains a string variable or an array.

The %= operator combines two operations. First, it divides and determines the remainder, and then it assigns the remainder to the variable. Therefore, the following statements are equivalent:

The following example shows how to use the %= operator to save the modulus of a quotient:

The increment and decrement operators

The increment operator ++ increases the value of a variable by 1. When you use the increment operator in a simple statement, no value is returned. To view the result, display the value of the variable, as follows:

To force a value to be returned, enclose the variable and the operator in parentheses, as follows:

The increment operator can be placed before (prefix) or after (postfix) a variable. The prefix version of the operator increments a variable before its value is used in the statement, as follows:

The postfix version of the operator increments a variable after its value is used in the statement. In the following example, the $c and $a variables have different values because the value is assigned to $c before $a changes:

The decrement operator -- decreases the value of a variable by 1. As with the increment operator, no value is returned when you use the operator in a simple statement. Use parentheses to return a value, as follows:

The prefix version of the operator decrements a variable before its value is used in the statement, as follows:

The postfix version of the operator decrements a variable after its value is used in the statement. In the following example, the $d and $a variables have different values because the value is assigned to $d before $a changes:

Null-coalescing assignment operator

The null-coalescing assignment operator ??= assigns the value of its right-hand operand to its left-hand operand only if the left-hand operand evaluates to null. The ??= operator doesn't evaluate its right-hand operand if the left-hand operand evaluates to non-null.

For more information, see Null-coalescing operator .

Microsoft .NET types

By default, when a variable has only one value, the value that's assigned to the variable determines the data type of the variable. For example, the following command creates a variable that has the System.Int32 type:

To find the .NET type of a variable, use the GetType method and its FullName property. Be sure to include the parentheses after the GetType method name, even though the method call has no arguments:

To create a variable that contains a string, assign a string value to the variable. To indicate that the value is a string, enclose it in quotation marks, as follows:

If the first value that's assigned to the variable is a string, PowerShell treats all operations as string operations and casts new values to strings. This occurs in the following example:

If the first value is an integer, PowerShell treats all operations as integer operations and casts new values to integers. This occurs in the following example:

You can cast a new scalar variable as any .NET type by placing the type name in brackets that precede either the variable name or the first assignment value. When you cast a variable, you are defining the type of data that can be stored in the variable.

For example, the following command casts the variable as a string type:

The following example casts the first value, instead of casting the variable:

You can't recast the data type of an existing variable if its value can't be converted to the new data type.

To change the data type, you must replace its value, as follows:

In addition, when you precede a variable name with a data type, the type of that variable is locked unless you explicitly override the type by specifying another data type. If you try to assign a value that's incompatible with the existing type, and you don't explicitly override the type, PowerShell displays an error, as shown in the following example:

In PowerShell, the data types of variables that contain multiple items in an array are handled differently from the data types of variables that contain a single item. Unless a data type is specifically assigned to an array variable, the data type is always System.Object [] . This data type is specific to arrays.

Sometimes, you can override the default type by specifying another type. For example, the following command casts the variable as a string [] array type:

PowerShell variables can be any .NET data type. In addition, you can assign any fully qualified .NET data type that's available in the current process. For example, the following command specifies a System.DateTime data type:

The variable will be assigned a value that conforms to the System.DateTime data type. The value of the $a variable would be the following:

Assigning multiple variables

In PowerShell, you can assign values to multiple variables using a single command. The first element of the assignment value is assigned to the first variable, the second element is assigned to the second variable, the third element to the third variable. This is known as multiple assignment .

For example, the following command assigns the value 1 to the $a variable, the value 2 to the $b variable, and the value 3 to the $c variable:

If the assignment value contains more elements than variables, all the remaining values are assigned to the last variable. For example, the following command contains three variables and five values:

Therefore, PowerShell assigns the value 1 to the $a variable and the value 2 to the $b variable. It assigns the values 3, 4, and 5 to the $c variable. To assign the values in the $c variable to three other variables, use the following format:

This command assigns the value 3 to the $d variable, the value 4 to the $e variable, and the value 5 to the $f variable.

If the assignment value contains fewer elements than variables, the remaining variables are assigned the value $null . For example, the following command contains three variables and two values:

Therefore, PowerShell assigns the value 1 to the $a variable and the value 2 to the $b variable. The $c variable is $null .

You can also assign a single value to multiple variables by chaining the variables. For example, the following command assigns a value of "three" to all four variables:

Variable-related cmdlets

In addition to using an assignment operation to set a variable value, you can also use the Set-Variable cmdlet. For example, the following command uses Set-Variable to assign an array of 1, 2, 3 to the $a variable.

  • about_Arrays
  • about_Hash_Tables
  • about_Variables
  • Clear-Variable
  • Remove-Variable
  • Set-Variable

Submit and view feedback for

Additional resources

  • 90% Refund @Courses
  • C++ Data Types
  • C++ Input/Output
  • C++ Pointers
  • C++ Interview Questions
  • C++ Programs
  • C++ Cheatsheet
  • C++ Projects
  • C++ Exception Handling
  • C++ Memory Management

Related Articles

  • Solve Coding Problems
  • C++ Ternary or Conditional Operator
  • C++ Logical Operators
  • C++ Relational Operators
  • Increment (++) and Decrement (--) Operator Overloading in C++
  • Types of Operator Overloading in C++
  • Typecast Operator Overloading in C++
  • Casting Operators in C++
  • How to Lock Window Resize C++ sfml?
  • How to Overload == Operator in C++?
  • C++ Arithmetic Operators
  • dot (.) operator in C++
  • Increment Operator Behavior When Passed as Function Parameters in C++
  • Overloading of function-call operator in C++
  • Constants in C++
  • C++ Program For Iterative Quick Sort
  • C++ sizeof Operator
  • C++ Increment and Decrement Operators
  • C++ Comparison Operators
  • Bitwise Operators in C++

C++ Assignment Operator Overloading

Prerequisite: Operator Overloading

The assignment operator,”=”, is the operator used for Assignment. It copies the right value into the left value. Assignment Operators are predefined to operate only on built-in Data types.

  • Assignment operator overloading is binary operator overloading.
  • Overloading assignment operator in C++ copies all values of one object to another object.
  • Only a non-static member function should be used to overload the assignment operator.

We can’t directly use the Assignment Operator on objects. The simple explanation for this is that the Assignment Operator is predefined to operate only on built-in Data types. As the class and objects are user-defined data types, so the compiler generates an error.

here, a and b are of type integer, which is a built-in data type. Assignment Operator can be used directly on built-in data types.

c1 and c2 are variables of type “class C”. Here compiler will generate an error as we are trying to use an Assignment Operator on user-defined data types.

The above example can be done by implementing methods or functions inside the class, but we choose operator overloading instead. The reason for this is, operator overloading gives the functionality to use the operator directly which makes code easy to understand, and even code size decreases because of it. Also, operator overloading does not affect the normal working of the operator but provides extra functionality to it.

Now, if the user wants to use the assignment operator “=” to assign the value of the class variable to another class variable then the user has to redefine the meaning of the assignment operator “=”.  Redefining the meaning of operators really does not change their original meaning, instead, they have been given additional meaning along with their existing ones.

Whether you're preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, GeeksforGeeks Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we've already empowered, and we're here to do the same for you. Don't miss out - check it out now !

Please Login to comment...

  • cpp-operator
  • cpp-operator-overloading
  • Apple's New AI-powered Tool: Editing Through Text Prompts
  • Rebranding Google Bard to Gemini: All You Need to Know, Android App and Advanced subscriptions
  • Youtube TV's Multiview Update: Tailor Your Experience in 4 Easy Steps
  • Kore.ai Secures $150 Million for AI-Powered Growth
  • 10 Best IPTV Service Provider Subscriptions

Improve your Coding Skills with Practice

 alt=

What kind of Experience do you want to share?

  • Skip to main content
  • Skip to search
  • Skip to select language
  • Sign up for free
  • English (US)

Spread syntax (...)

The spread ( ... ) syntax allows an iterable, such as an array or string, to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected. In an object literal, the spread syntax enumerates the properties of an object and adds the key-value pairs to the object being created.

Spread syntax looks exactly like rest syntax. In a way, spread syntax is the opposite of rest syntax. Spread syntax "expands" an array into its elements, while rest syntax collects multiple elements and "condenses" them into a single element. See rest parameters and rest property .

Description

Spread syntax can be used when all elements from an object or array need to be included in a new array or object, or should be applied one-by-one in a function call's arguments list. There are three distinct places that accept the spread syntax:

  • Function arguments list ( myFunction(a, ...iterableObj, b) )
  • Array literals ( [1, ...iterableObj, '4', 'five', 6] )
  • Object literals ( { ...obj, key: 'value' } )

Although the syntax looks the same, they come with slightly different semantics.

Only iterable values, like Array and String , can be spread in array literals and argument lists. Many objects are not iterable, including all plain objects that lack a Symbol.iterator method:

On the other hand, spreading in object literals enumerates the own properties of the value. For typical arrays, all indices are enumerable own properties, so arrays can be spread into objects.

All primitives can be spread in objects. Only strings have enumerable own properties, and spreading anything else doesn't create properties on the new object.

When using spread syntax for function calls, be aware of the possibility of exceeding the JavaScript engine's argument length limit. See Function.prototype.apply() for more details.

Spread in function calls

Replace apply().

It is common to use Function.prototype.apply() in cases where you want to use the elements of an array as arguments to a function.

With spread syntax the above can be written as:

Any argument in the argument list can use spread syntax, and the spread syntax can be used multiple times.

Apply for new operator

When calling a constructor with new , it's not possible to directly use an array and apply() , because apply() calls the target function instead of constructing it, which means, among other things, that new.target will be undefined . However, an array can be easily used with new thanks to spread syntax:

Spread in array literals

A more powerful array literal.

Without spread syntax, the array literal syntax is no longer sufficient to create a new array using an existing array as one part of it. Instead, imperative code must be used using a combination of methods, including push() , splice() , concat() , etc. With spread syntax, this becomes much more succinct:

Just like spread for argument lists, ... can be used anywhere in the array literal, and may be used more than once.

Copying an array

You can use spread syntax to make a shallow copy of an array. Each array element retains its identity without getting copied.

Spread syntax effectively goes one level deep while copying an array. Therefore, it may be unsuitable for copying multidimensional arrays. The same is true with Object.assign() — no native operation in JavaScript does a deep clone. The web API method structuredClone() allows deep copying values of certain supported types . See shallow copy for more details.

A better way to concatenate arrays

Array.prototype.concat() is often used to concatenate an array to the end of an existing array. Without spread syntax, this is done as:

With spread syntax this becomes:

Array.prototype.unshift() is often used to insert an array of values at the start of an existing array. Without spread syntax, this is done as:

With spread syntax, this becomes:

Note: Unlike unshift() , this creates a new arr1 , instead of modifying the original arr1 array in-place.

Conditionally adding values to an array

You can make an element present or absent in an array literal, depending on a condition, using a conditional operator .

When the condition is false , we spread an empty array, so that nothing gets added to the final array. Note that this is different from the following:

In this case, an extra undefined element is added when isSummer is false , and this element will be visited by methods such as Array.prototype.map() .

Spread in object literals

Copying and merging objects.

You can use spread syntax to merge multiple objects into one new object.

A single spread creates a shallow copy of the original object (but without non-enumerable properties and without copying the prototype), similar to copying an array .

Overriding properties

When one object is spread into another object, or when multiple objects are spread into one object, and properties with identical names are encountered, the property takes the last value assigned while remaining in the position it was originally set.

Conditionally adding properties to an object

You can make an element present or absent in an object literal, depending on a condition, using a conditional operator .

The case where the condition is false is an empty object, so that nothing gets spread into the final object. Note that this is different from the following:

In this case, the watermelon property is always present and will be visited by methods such as Object.keys() .

Because primitives can be spread into objects as well, and from the observation that all falsy values do not have enumerable properties, you can simply use a logical AND operator:

In this case, if isSummer is any falsy value, no property will be created on the fruits object.

Comparing with Object.assign()

Note that Object.assign() can be used to mutate an object, whereas spread syntax can't.

In addition, Object.assign() triggers setters on the target object, whereas spread syntax does not.

You cannot naively re-implement the Object.assign() function through a single spreading:

In the above example, the spread syntax does not work as one might expect: it spreads an array of arguments into the object literal, due to the rest parameter. Here is an implementation of merge using the spread syntax, whose behavior is similar to Object.assign() , except that it doesn't trigger setters, nor mutates any object:

Specifications

Browser compatibility.

BCD tables only load in the browser with JavaScript enabled. Enable JavaScript to view data.

  • Rest parameters
  • Rest property
  • Function.prototype.apply()

IMAGES

  1. Operadores de asignación en C/C++

    operator assign to

  2. Assignment Operators in C Programming

    operator assign to

  3. Python Operators

    operator assign to

  4. Operator assignment

    operator assign to

  5. PPT

    operator assign to

  6. Pointer Expressions in C with Examples

    operator assign to

VIDEO

  1. Module 2|Part 2|Operator Overloading|Object Oriented Programming|KTU|C++

  2. Operator Framework SIG 2020-02-18 Full Meeting Recording

  3. walrus operator in Python #programming #data #python

  4. Operator Help

  5. what is unary operator #operator #coding #java #shorts #javaquestions #easytounderstand #subscribe

  6. Assignment Operator Overloading in C++

COMMENTS

  1. Assignment (=)

    The assignment ( =) operator is used to assign a value to a variable or property. The assignment expression itself has a value, which is the assigned value. This allows multiple assignments to be chained in order to assign a single value to multiple variables. Try it Syntax js x = y Parameters x

  2. Assignment Operators in C

    1. "=": This is the simplest assignment operator. This operator is used to assign the value on the right to the variable on the left. Example: a = 10; b = 20; ch = 'y'; 2. "+=": This operator is combination of '+' and '=' operators.

  3. Assignment operators

    Assignment operators modify the value of the object. Syntax Over load able Prototype examples (for replaces the contents of the object is not modified). For class types, this is performed in a special member function, described in For non-class types, copy and move assignment are indistinguishable and are referred to as

  4. Assignment operators

    The assignment operator = assigns the value of its right-hand operand to a variable, a property, or an indexer element given by its left-hand operand. The result of an assignment expression is the value assigned to the left-hand operand.

  5. Assignment Operators In C++

    There are 10 compound assignment operators in C++: Addition Assignment Operator ( += ) Subtraction Assignment Operator ( -= ) Multiplication Assignment Operator ( *= ) Division Assignment Operator ( /= ) Modulus Assignment Operator ( %= ) Bitwise AND Assignment Operator ( &= ) Bitwise OR Assignment Operator ( |= )

  6. Expressions and operators

    This chapter describes JavaScript's expressions and operators, including assignment, comparison, arithmetic, bitwise, logical, string, ternary and more. At a high level, an expression is a valid unit of code that resolves to a value. There are two types of expressions: those that have side effects (such as assigning values) and those that ...

  7. Assignment operators

    function call, comma, conditional operator. [edit] Assignment and compound assignment operators are binary operators that modify the variable to their left using the value to their right. becomes equal to. becomes equal to the addition of. becomes equal to the subtraction of. becomes equal to the product of. becomes equal to the division of.

  8. Assignment Operators in C

    Assignment Operators in C The following table lists the assignment operators supported by the C language − Example Try the following example to understand all the assignment operators available in C − Live Demo

  9. Assignment operators

    The simple assignment operator ( =) causes the value of the second operand to be stored in the object specified by the first operand. If both objects are of arithmetic types, the right operand is converted to the type of the left, before storing the value.

  10. C Operators

    Operators. Operators are used to perform operations on variables and values. In the example below, we use the + operator to add together two values: Example. int myNum = 100 + 50; Try it Yourself ». Although the + operator is often used to add together two values, like in the example above, it can also be used to add together a variable and a ...

  11. Operators

    The assignment operator (operator =, with one equal sign) is not the same as the equality comparison operator (operator ==, with two equal signs); the first one (=) assigns the value on the right-hand to the variable on its left, while the other (==) compares whether the values on both sides of the operator are equal.

  12. JavaScript Assignment

    Assignment operators assign values to JavaScript variables. Shift Assignment Operators Bitwise Assignment Operators Logical Assignment Operators Note The Logical assignment operators are ES2020 . The = Operator The Simple Assignment Operator assigns a value to a variable. Simple Assignment Examples let x = 10; Try it Yourself » let x = 10 + y;

  13. C++ Assignment Operators

    Assignment operators are used to assign values to variables. In the example below, we use the assignment operator ( =) to assign the value 10 to a variable called x: Example int x = 10; Try it Yourself » The addition assignment operator ( +=) adds a value to a variable: Example int x = 10; x += 5; Try it Yourself »

  14. Assignment Operators in Python

    1) Assign: This operator is used to assign the value of the right side of the expression to the left side operand. Syntax: x = y + z Example: Python3 a = 3 b = 5 c = a + b print(c) Output: 8 2) Add and Assign: This operator is used to add the right side operand with the left side operand and then assigning the result to the left operand. Syntax:

  15. Python's Assignment Operator: Write Robust Assignments

    The Assignment Operator Assignments and Variables Other Assignment Syntax Assignment Statements in Action Initializing and Updating Variables Making Multiple Variables Refer to the Same Object Updating Lists Through Indices and Slices Adding and Updating Dictionary Keys Doing Parallel Assignments Unpacking Iterables

  16. about Assignment Operators

    <operator><assignable-expression> The value of the assignable expression must be a number or it must be convertible to a number. Using the assignment operator Variables are named memory spaces that store values. You store the values in variables using the assignment operator =.

  17. c++

    The assignment operator behaves as-expected, outputting the address of the other instance. Now, how would I actually assign something from the other instance? For example, something like this: void operator= (TestClass Other) { ClassName = Other.ClassName; } c++ class operators operator-overloading assignment-operator Share Improve this question

  18. Operators in Programming

    Assignment operators in programming are used to assign values to variables. They are essential for storing and updating data within a program. Here are common assignment operators: Operator Description Examples = (Assignment) Assigns the value on the right to the variable on the left.

  19. Logical OR assignment (||=)

    The logical OR assignment ( ||=) operator only evaluates the right operand and assigns to the left if the left operand is falsy. Try it Syntax js x ||= y Description Logical OR assignment short-circuits, meaning that x ||= y is equivalent to x || (x = y), except that the expression x is only evaluated once.

  20. How to generalize a struct to an int with the assignment operator?

    On the bright-side, I can see that my struct is 4 bytes, and I am able to assign a 32-bit integer to the struct. However, I cannot assign the struct to a 32-bit integer. I'm sure the syntax for the following method is completely wrong, but I don't know how and the compiler isn't helping me.

  21. Java Assignment Operators with Examples

    Practice Operators constitute the basic building block of any programming language. Java too provides many types of operators which can be used according to the need to perform various calculations and functions, be it logical, arithmetic, relational, etc. They are classified based on the functionality they provide. Types of Operators:

  22. C++ Assignment Operator Overloading

    The assignment operator,"=", is the operator used for Assignment. It copies the right value into the left value. Assignment Operators are predefined to operate only on built-in Data types. Assignment operator overloading is binary operator overloading. Overloading assignment operator in C++ copies all values of one object to another object.

  23. Spread syntax (...)

    The spread (...) syntax allows an iterable, such as an array or string, to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected. In an object literal, the spread syntax enumerates the properties of an object and adds the key-value pairs to the object being created. Spread syntax looks exactly like rest syntax.