C :

#include <stdio.h>

int main()
{
  int year, leap;

  scanf("%d", &year);
  leap = 0; //0表示非闰年
  if(year % 4 == 0){
    if(year % 100 != 0)
      leap = 1;
  }
  if(year % 400 == 0)
    leap = 1;
  if(leap)
    printf("yes\n");
  else
    printf("no\n");

  return 0;
}

C++ :

#include<iostream>
using namespace std;
int main()
{
int a;
cin>>a;
if(a%4==0&&a%100!=0||a%400==0)
cout<<"yes"<<endl;
else cout<<"no"<<endl;
}

Pascal :

program Jerry001;
var a:integer;
begin
readln(a);
if (a mod 4=0) and (a mod 100<>0) then writeln('yes')
else if a mod 400=0 then writeln('yes')
else writeln('no');
end.