怎么快速计算今天是今年的第几天答:include <stdio.h> 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; case 4:...