C #define macros

Question

Here is what i have and I wonder how this works and what it actually does.

#define NUM 5
#define FTIMES(x)(x*5)

int main(void) {
    int j = 1;
    printf(\         


        

Answer 1

The compiler pre-process simply does a substitution of FTIMES wherever it sees it, and then compiles the code. So in reality, the code that the compiler sees is this:

#define NUM 5
#define FTIMES(x)(x*5)

int main(void)
{

    int j = 1;

    printf("%d %d\n", j+5*5,(j+5)*5);
}

Then, taking operator preference into account, you can see why you get 26 and 30.