Write a line in program that looks useless Write some program (the size doesn't matter), and put a line that looks useless, but it's actually not - if it would be removed, the program would crash, or do something wrong. Feel free to mark the line that looks unused by a comment, or mention it your code description, like in example below (of course, in this example, the line is actually not needed, it's just an example).

int main(void) {
    /* The line below is actually needed. */
    2 + 2;

    return 0;
}


As this is popularity contest, the solution with highest number of votes wins.
C

int main(int argc, char **argv) {
    switch(argc) {
        case 2:
            ;
            int allowed = 0;
        case 3:
            argc--;
            break;
        default:
            argc = 3;
    }
    return 0;
}


Won't compile if we remove the single ;.

EDIT:

Solution below:


   This happens because a case statement is just a label, and, as such, must be followed by a statement (which the standard refers to as a "specifier for actions to be performed", which rules out declarations). To prevent this, we prefix the declaration with a ;, a null statement. Specifications for the case label can be found here at page 142 (131 in-document)