#include <stdio.h>
char a[XXX];
char b[1];
int main(){printf("%d ",b-a);return 0;}

for XXX in 1 2 3 4 5 6 7 8 9 10; do gcc -DXXX=$XXX hoge.c; ./a.out; done

結果
1 2 3 4 5 6 7 8 9 10