while loop

    while ( expression ) {
        statement;
    }

• The expression is evaluated;
• If it is non-zero, statement is executed;
• The expression is re-evaluated.
• Therefore, while continues cycling until expression becomes zero:

        int main()
        {
            int x = 0;
            while ( x < 5 ) { // condition
                // loop body:
                x = x + 1;
            }  
            return 0;
        }