HELP: C programming

Question

Why will the following question produce 3, instead of 4?

#include <stdio.h>
#define square(x) (x*x)

int main() {
int x, y = 1;
x=square(y+1);
printf("%d\n",x);
return 0;
}

Answer 1

#define is a macro, it will just replace square(expressions) by expression*expression. so

x=square(y+1)=y+1*y+1=1+1*1+1=3

if you want it to really calculate the square, use:
#define square(x) (x)*(x)

Answer 2

I'm saved, thank you John Robotane 😆