今年过去了多少天？（switch）

//今年已经过去了几天？
#include <stdio.h>
int monthday(int year,int month){switch(month){case 1:return 31;case 2:if ((year % 4 == 0 && year % 100 != 0)||year % 400 == 0){return 29;}else{return 28;}break;case 3:return 31;case 4:return 30;case 5:return 31;case 6:return 30;case 7:return 31;case 8:return 31;case 9:return 30;case 10:return 31;case 11:return 30;case 12:return 31;default:return 0;}
}
int main(){int year,month,day;scanf("%d %d %d",&year,&month,&day);int i=1;int sum=day;for(i=1;i<=month;i++){sum+=monthday(year,i-1);}if(sum==1){printf("So far 1 day");}else{printf("So far %d days",sum);}
}