编程题：用函数实现，用户输入年月日，来计算出该日期为当年第几天？
#include<stdio.h>
/*函数is_leap_year（）的返回值是判断该年是否闰年*/
int is_leap_year(int year)
{ int leap;
if(year%4==0&&year%100!=0||year%400==0) leap=1;
else leap=0;
return leap;
}
/*函数len_of_month()的返回值为某年year的某月month的天数*/
int len_of_month(int year,int month)
{ int month_days;
if(month==2)
if(is_leap_year(year)) month_days=29;
else month_days=28;
else if(month==4||month==6||month==9||month==11) month_days=30;
else month_days=31;
return month_days;
}
/*函数len_of_days()的返回值为该日期date是该年year的第几天*/
int len_of_days(int year,int month,int date)
{ int total_days,n;
for(n=1,total_days=0;n<month;n++)
total_days+=len_of_month(year,n);
total_days+=date;
return total_days;
}
void main()
{ int year,month,date,days,n;
printf("please input year,month,date:");
scanf("%d,%d,%d",&year,&month,&date);
days=len_of_days(year,month,date);
printf("%d/%d/%d is the %d in %d\n",year,month,date,days,year);
}
