c语言用switch输入1-7输出星期数。有一个小错误求解

#include <stdio.h>
int main()
{
int n;
scanf("%d",&n);
switch(n)
{
case 1:printf("Monday");break;
case 2:printf("Tuesday");break;
case 3:printf("Wednesday");break;
case 4:printf("Thursday");break;
case 5:printf("Friday");break;
case 6:printf("Saturday");break;
case 7:printf("Sunday");break;

}

return 0;

}

加个default

#include <stdio.h>
int main()
{
    int n;
    scanf("%d",&n);
    switch(n)
    {
    case 1:
        printf("Monday");
        break;
    case 2:
        printf("Tuesday");
        break;
    case 3:
        printf("Wednesday");
        break;
    case 4:
        printf("Thursday");
        break;
    case 5:
        printf("Friday");
        break;
    case 6:
        printf("Saturday");
        break;
    case 7:
        printf("Sunday");
        break;
        default:
        printf("NULL");
        break;
    }

    return 0;

}

没什么错误啊