Difference between revisions of "cpp/language/break"

Latest revision as of 11:16, 11 August 2024

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.

[edit] Syntax

[edit] Explanation

Appears only within the statement of a loop body (while, do-while, for) or within the statement of a switch. 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.

[edit] Notes

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

[edit] Keywords

break

[edit] Example

#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';
}

2345
a0 a1 b0 b1

[edit] See also