#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>

// // WRONG (naïve)
// #define  FIVE_PLUS(n)  5 + n

// FIXED
#define  FIVE_PLUS(n)  (5 + n)

int main(int argc, char* argv[]) {

    printf("%d\n",  FIVE_PLUS(100));  // ⇒ 105
    // Preprocessor will replace  FIVE_PLUS(100)  with  5 + 100.
    
    // This WILL work as you expect.
    printf("%d\n",  1000 * FIVE_PLUS(100));
    // Preprocessor will replace  FIVE_PLUS(100)  with  (5 + 100).
    // Statement will become:
    //   printf("%d\n",  1000 * (5 + 100));
    // Expect:  105000
    // Actual:  105000
    
    return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */