题解 | #获得月份天数#

#include <stdio.h>

int main() {
    int a, b;
    while (scanf("%d %d", &a, &b) != EOF) { 
        switch(b)
        {
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:
            printf("31\n");
            break;
            case 4:
            case 6:
            case 9:
            case 11:
            printf("30\n");
            break;
            case 2:
            if(a%100==0)
        {
            if(a%400==0)
            {
            printf("29\n" );
            }
            else
            {
            printf("28\n" );
            }
        }
        else 
        {
            if(a%4==0)
            {
              printf("29\n" );  
            }
            else{
             printf("28\n" );
            }
        }
        }
        
    }
    return 0;
}