请C语言高手帮帮我，编写程序。

swicth 两种用法。
只说说明了swicth用法，没有判断输入错误。

1.
#include<stdio.h>

int main(void)
{
int m,d;
int sum = 0;

printf("mm-dd:\n");
scanf("%d-%d", &m, &d);

for (m--; m > 0; m--)
switch (m) {
case 12: case 10: case 8: case 7: case 5: case 3: case 1:
sum += 31;
break;
case 11: case 9: case 6: case 4:
sum += 30;
break;
case 2:
sum += 28;
break;
default:
printf("ERRO\n");
return 0;
}

sum += d;

printf("%d\n", sum);

return 0;
}
------------------------------------------

2.
#include<stdio.h>

int main(void)
{
int m,d;
int sum = 0;

printf("mm-dd:\n");
scanf("%d-%d", &m, &d);

switch (m) {
case 12: