Using Exclamation Marks '!' in C

Question

I have come across a problem involving exclamation marks and integers whilst reading a code in my reference book.

Let us say I have declared an integer variable name

Answer 1

We can treat ! as not. So if a number is non-zero (either positive or negative) it returns Zero. If it is zero, it returns 1.

int i = 13;
printf("i = %d, !i = %d\n", i, !i);
printf("!0 = %d\n", !(0));