break statement

 

C++

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Named requirements

Feature test macros (C++20)

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Iterators library

Ranges library (C++20)

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Technical specifications

Symbols index

External libraries

 

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
Functions
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Lambda function expression
inline specifier
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noexcept specifier (C++11)
Exceptions
throw-expression	try-catch block
Namespaces
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Specifiers
decltype (C++11) auto (C++11) alignas (C++11)	const/volatile constexpr (C++11)
Storage duration specifiers
Initialization
Default initialization Value initialization Zero initialization Copy initialization Direct initialization	Aggregate initialization List initialization (C++11) Constant initialization Reference initialization

Expressions
Value categories Order of evaluation	Operators Operator precedence
Alternative representations
Literals
Boolean - Integer - Floating-point
Character - String - nullptr (C++11)
User-defined (C++11)
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Types
typedef declaration
Type alias declaration (C++11)
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static_cast - dynamic_cast
const_cast - reinterpret_cast
Memory allocation
new expression	delete expression
Classes
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Virtual function override specifier (C++11) final specifier (C++11)	explicit (C++11) static
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Default constructor Copy constructor Move constructor (C++11)	Copy assignment Move assignment (C++11) Destructor
Templates
Class template Function template	Template specialization Parameter packs (C++11)
Miscellaneous
Inline assembly	History of C++

 

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

Transactional memory

synchronized, atomic_commit, etc(TM TS)

 

Causes the enclosing for, range-for, while or do-while loop or switch statement to terminate.

Used when it is otherwise awkward to terminate the loop using the condition expression and conditional statements.

Syntax

attr(optional) break ;

Explanation

After this statement the control is transferred to the statement immediately following the enclosing loop or switch. 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.

Keywords

break

Notes

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

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 (int j = 0; j < 2; j++) {
        for (int k = 0; k < 5; k++) {    //only this loop is affected by break
            if (k == 2) break;           //
            std::cout << j << k << ' ';  //
        }
    }
}

Possible output:

2345
00 01 10 11

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