why there is semicolon after loop while();

Question

I am reading a code of my friend an I see this:

#include 
#include 

void main()
{
    char string1[125], string2 [10];
    in         


        

Answer 1

Usually, in a while loop, you have initialization, a comparison check, the loop body (some processing), and the iterator (usually either an addition of an index, or a pointer traversal e.g. next), something like this:

index = 0 // initialization
while(index < 4) { // comparison, loop termination check
     printf('%c\n', mystring[index]); // Some processing
     index += 1; // iterate to next loop
}

Without at least the last item, you won't ever exit the loop, so normally the loop body has more than one statement in it. In this case, they use post-increments like this:

while (string1[i++] == string2[j++]);

This does the comparison (the ==) and the iteration (the post-increment ++) in the comparison statement itself, and has no body, so there's no reason to add any other statements. A blank loop body can be represented by just a semicolon.