输入某年某月某日，判断这一天是这一年的第几天？//pta

#include<stdio.h>
int main()
{
  int year = 0, month = 0, day = 0, sum = 0;
  scanf("%d/%d/%d", &year, &month, &day);
  switch (month)
  {
  case(12):
    sum = day + 30;
  case(11):
    sum = day + 31;
  case(10):
    sum = day + 30;
  case(9):
    sum = day + 31;
  case(8):
    sum = day + 31;
  case(7):
    sum = day + 30;
  case(6):
    sum = day + 31;
  case(5):
    sum = day + 30;
  case(4):
    sum = day + 31;
  case(3):
  {
    if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0)
      sum = day + 29;
    else
      sum = day + 28;
  }
  case(2):
    sum = day + 31;
  case(1):
    printf("%d", sum);

  }
  return 0;
}