break statement

 

C++

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C++ language

General topics
Preprocessor Comments	Keywords Escape sequences
Flow control
Conditional execution statements
if	switch
Iteration statements (loops)
for range-for (C++11)	while do-while
Jump statements
continue - break	goto - return
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Inline assembly	History of C++

 

Statements

Labels
label : statement
Expression statements
expression ;
Compound statements
{ statement... }
Selection statements
if	switch
Iteration statements
while for	do while range for (C++11)
Expansion statements
template for (C++26)
Jump statements
break return	continue goto
Assertion statements
contract_assert (C++26)
Declaration statements
declaration ;
Try blocks
try block
Transactional memory
synchronized etc (TM TS)

 

See More

Terminates specific enclosing statements.

Syntax

attr (optional) break ;

attr

-

(since C++11) any number of attributes

Explanation

break statements must be enclosed by any of the following statements:

• iteration statements (for, range-for, while or do-while)

expansion statements (template for)

(since C++26)

• switch statements

Executing a break statement causes termination of the innermost such enclosing statement, then control passes to the statement following the terminated statement (if any).

Notes

As with any block exit, all automatic storage objects declared in enclosing compound statement or in the condition of a loop/switch are destroyed, in reverse order of construction, before the execution of the first line following the enclosing loop.

A break statement cannot be used to break out of multiple nested loops. The goto statement may be used for this purpose.

Keywords

break

Example

Run this code

#include <iostream>

int main()
{
    int i = 2;
    switch (i)
    {
        case 1: std::cout << "1";   // <---- maybe warning: fall through
        case 2: std::cout << "2";   // execution starts at this case label (+warning)
        case 3: std::cout << "3";   // <---- maybe warning: fall through
        case 4:                     // <---- maybe warning: fall through
        case 5: std::cout << "45";  //
                break;              // execution of subsequent statements is terminated
        case 6: std::cout << "6";
    }
    std::cout << '\n';
    
    for (char c = 'a'; c < 'c'; c++)
    {
        for (int i = 0; i < 5; i++)      // only this loop is affected by break
        {                                //
            if (i == 2)                  //
                break;                   //
            std::cout << c << i << ' ';  //
        }
    }
    std::cout << '\n';
}

Possible output:

2345
a0 a1 b0 b1

See also

[[fallthrough]] (C++17)	indicates that the fall through from the previous case label is intentional and should not be diagnosed by a compiler that warns on fall-through (attribute specifier)
C documentation for break