while

while (condition is true/untrue) {
    statement;
}
 
or 
 
while ( condition == true ) {
    do something until condition untrue
    }

while example objective c

        NSInteger i=0;
         while (i < 42) {
                i++;
                if (i==42) NSLog(@"whoooha ");
        }

  2012-10-12 00:59:38.184 cppApp[42258:c07] whoooha