代码清单1-7

struct {
unsigned char a:4;
unsigned char b:4;
} i;

for(i.a = 1; i.a <= 9; i.a++)
for(i.b = 1; i.b <= 9; i.b++)
if(i.a % 3 != i.b % 3)
printf(“A = %d, B = %d\n”, i.a, i.b);