unreal.c

/* stupid C puzzle: without trying it in the computer, explain why
 * does this not work
 */

#include <stdio.h>

#define NR1 5
#define NR2 4
#define NR3 3
#define NR4 2

#define GETNR(_N) NR##_N

int main(int argc, char *argv[])
{
    for (int i=0; i<4; i++) {
        printf("The value of number %d is %d\n", i, GETNR(i));
    }
}