c语言输入某年某月某日 判断这一天是这一年的第几天用switch答:include "stdio.h"#include "conio.h"int main(){int day,month,year,sum,leap;printf("\nplease input year,month,day\n");scanf("%d,%d,%d",&year,&month,&day);switch(month) /*先计算某月以前月份的总天数*/{case 1:sum=0;break;case 2:sum=31;break;case 3:sum=59;break;...