return statement

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

C++ language

 

Statements

Labels

label : statement

Expression statements

expression ;

Compound statements

{ statement... }

Selection statements

if

switch

Iteration statements

while

do-while

for

range for(C++11)

Jump statements

break

continue

return

goto

Declaration statements

declaration ;

Try blocks

try compound-statement handler-sequence

 

Terminates current function and returns specified value to the caller function.

Syntax

attr(optional) return expression(optional) ;	(1)
attr(optional) return braced-init-list ;	(2)	(since C++11)

attr(C++11)	-	optional sequence of any number of attributes
expression	-	expression, convertible to the function return type
braced-init-list	-	brace-enclosed list of initializers and other braced-init-lists

Explanation

1) Evaluates the expression, terminates the current function and returns the result of the expression to the caller, after implicit conversion to the function return type. The expression is optional in functions whose return type is (possibly cv-qualified) void, in constructors and in destructors.

2) Uses copy-list-initialization to construct the return value of the function.

Notes

If control reaches the end of a function without encountering a return statement, return; is executed (except in the main function, where return 0; is executed).

Flowing off the end of a value-returning function (except main) without a return statement is undefined behavior.

In a function returning void, the return statement with expression can be used, if the expression type is void.

Returning by value may involve construction and copy/move of a temporary object, unless copy elision is used.

Keywords

return

Example

run this code

#include <iostream>
#include <string>
#include <utility>
 
void fa(int i)
{
    if (i == 2)
         return;
    std::cout << i << '\n';
} // implied return;
 
int fb(int i)
{
    if (i > 4)
         return 4;
    std::cout << i << '\n';
    return 2;
}
 
std::pair<std::string, int> fc(const char* p, int x)
{
    return {p, x};
}
 
void fd()
{
    return fa(10); // fa(10) is a void expression
}
 
int main()
{
    fa(2); // returns, does nothing when i==2
    fa(1); // prints its argument, then returns
    int i = fb(5); // prints its argument, returns 2
    i = fb(i); // prints its argument, returns 4
    std::cout << i << '\n'
              << fc("Hello", 7).second << '\n';;
    fd();
}

Output:

1
4
2
7
10