The remainder operator (otherwise known as the modulo operator) % is a binary operator (i.e., takes exactly 2 operands) and operates only on integer types (e.g., short, int, long, long long, etc).

$ vim using_mod.c

#include <stdio.h>
int main(void) {
float num = 6.00;
int remainder = (int)num % (int)3.0;
if (remainder == 0) {
printf("number is divisible\n");
} else {
printf("number is not divisible: Remainder = %d\n", remainder);
}
return 0;
}

$ gcc -o using_mod using_mod.c

$ ./using_mod
number is divisible

Now, if we change the number from 6 to something else, for example 11, the output will be as below,

$ ./using_mod
number is not divisible: Remainder = 2

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