Why this code returns 3?

Question

https://code.sololearn.com/cT1RXh2eishj/?ref=app

Answer 1

When the macro (x*x) gets expanded it simply replaces x with y+1. See what happens when it does that:

(x*x) becomes (y+1*y+1)

Now do the math.

Answer 2

#define square(x) (x*x)
int main() {
int x, y=1;
x=square(y+1);

/*
here square(y+1) is just replaced as (y+1*y+1)
and then evaluated as
x = y+1*y+1
=1+1*1+1
=1+1+1
= 3
so x=3

if you define square (x) as ((x)*(x)) then output you get as 4
*/

printf("%d\n",x);
return 0;
}

//hope it helps....

Answer 3

Jayakrishna🇮🇳 thanks I got it...

Answer 4

Roshan Diwan check again, please. If y=1:

(y+1*y+1) becomes (1+1*1+1)

It reduces to (1+1+1) = 3.

Answer 5

Brian thanks, now it's more clear to me...