C :

#include<stdio.h>
int ok(int n)
{
	if(n%100==0)
	{if(n%400==0) return 1;
	else return 0;
	}
	else if( n%4==0) return 1;
	else return 0;
}
int main()
{
  int i,x,y,z,sum=0;
  int a[]={31,29,31,30,31,30,31,31,30,31,30,31};
  int b[]={31,28,31,30,31,30,31,31,30,31,30,31};
  scanf("%d%d%d",&x,&y,&z);
if(ok(x))
{
	for(i=1;i<y;i++) sum+=a[i-1];
	sum+=z;
}
else
{
	for(i=1;i<y;i++) sum+=b[i-1];
	sum+=z;
}
printf("%d\n",sum);
  return 0;
}

C++ :

#include <stdio.h>
struct date {
	int year, month, day;
};
int main() {
	int days(struct date today);
	struct date today;
	scanf("%d %d %d", &today.year, &today.month, &today.day);
	printf("%d\n", days(today));
	return 0;
}
/* 计算输入的日期是当年的第几天 */
int days(struct date today) {
	int is_leap_year(int year);
	int day_of_month[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
	int i, totdays = 0;
	for (i = 1;i < today.month;i++) {
		totdays += day_of_month[i - 1];
		if (i == 2 && is_leap_year(today.year) == 1)
			totdays++;
	}
	totdays += today.day;
	return totdays;
}
/* 判断是否是闰年 */
int is_leap_year(int year) {
	if (year % 4 == 0) {
		if (year % 100 == 0 && year % 400 != 0)
			return 0;
		return 1;
	}
	return 0;
}

Pascal :

var
  year,month,day,len:integer;
begin
  readln(year,month,day);
  if month=1 then len:=day;
  if month=2 then len:=31+day;
  if month=3 then len:=31+28+day;
  if month=4 then len:=31+28+31+day;
  if month=5 then len:=31+28+31+30+day;
  if month=6 then len:=31+28+31+30+31+day;
  if month=7 then len:=31+28+31+30+31+30+day;
  if month=8 then len:=31+28+31+30+31+30+31+day;
  if month=9 then len:=31+28+31+30+31+30+31+31+day;
  if month=10 then len:=31+28+31+30+31+30+31+31+30+day;
  if month=11 then len:=31+28+31+30+31+30+31+31+30+31+day;
  if month=12 then len:=31+28+31+30+31+30+31+31+30+31+30+day;
  if (month>2) and ((year mod 400=0) or ((year mod 4=0) and (year mod 100<>0))) then
  len:=len+1;
  writeln(len);
end.

Java :

import java.util.Scanner;

public class Main{
   private static Scanner s =new Scanner(System.in) ;
   
   public static void main(String[] args) {
	  int year = s.nextInt() ;
	  int month = s.nextInt() ;
	  int day = s.nextInt() ;
	  if(1000<=year&&year<=3000){
		  System.out.println(get(year, month, day));
	  }
   }
   
   static int get(int year , int month , int day){
	   int temp = getDay(year, month) ;
	   return temp + day ;
   }
   
   static boolean isLeap(int year){
	   if(year%4==0){
		   if(year%100==0){
			   if(year%400==0){
				   return true ;
			   }else return false ;
		   }
		   return true ;
	   }
	   else return false ;
   }
   
   static int getDay(int year , int month){
	   int day = 0 ;
	   if(month>=1){
		   day = 0 ;
	   }if(month>=2){
		   day = day + 31 ;
	   }if(month>=3){
		   if (isLeap(year)) {
				day =day+ 29 ;
				
			}
			   else day =day+ 28 ;
	   }if(month>=4){
		   day = day + 31 ;
	   }if(month>=5){
		   day = day + 30 ;
	   }if(month>=6){
		   day = day + 31 ;
	   }if(month>=7){
		   day = day + 30 ;
	   }if(month>=8){
		   day = day + 31 ;
	   }if(month>=9){
		   day = day + 31 ;
	   }if(month>=10){
		   day = day + 30 ;
	   }if(month>=11){
		   day = day + 31 ;
	   }if(month>=12){
		   day = day + 30 ;
	   }
	   return day ;
   }
}