题解 | 计算日期到天数转换

#include <stdio.h>

int main() {

    int year=0;
    int mon=0;
    int day=0;
    scanf("%d",&year);
    scanf("%d",&mon);
    scanf("%d",&day);
    int op=0;
    op=(mon-1)*30+day;
    for(int i=mon-1; i!=0; i--)
    {
        switch (i)
        {
            case 1:
              op++;break;
            case 3:
              op++;break;
            case 5:
              op++;break;
            case 7:
              op++;break;
            case 8:
              op++;break;
            case 10:
              op++;break;
            case 12:
              op++;break;
        }

    }
   if(mon>2)
 {   if((year%4==0&&year%100!=0)||year%400==0)
    op=op-1;
    else op=op-2;
 }
    printf("%d",op);
 
    return 0;
}