do-while loop

Conditionally executes a statement repeatedly (at least once).

Syntax

Explanation

When control reaches a do statement, its statement will be executed unconditionally.

Every time statement finishes its execution, expression will be evaluated and contextually converted to bool. If the result is true, statement

If the loop needs to be terminated within statement, a break statement

If the current iteration needs to be terminated within statement, a continue statement

Notes

As part of the C++ forward progress guarantee, the behavior is undefined if a loop that is not a trivial infinite loop (since C++26) without observable behavior

Keywords

do, while

Example

#include <algorithm>
#include <iostream>
#include <string>
 
int main()
{
    int j = 2;
    do // compound statement is the loop body
    {
        j += 2;
        std::cout << j << ' ';
    }
    while (j < 9);
    std::cout << '\n';
 
    // common situation where do-while loop is used
    std::string s = "aba";
    std::sort(s.begin(), s.end());
 
    do std::cout << s << '\n'; // expression statement is the loop body
    while (std::next_permutation(s.begin(), s.end()));
}

4 6 8 10
aab
aba
baa

See also