C :

#include "stdio.h"

int main(int argc, char* argv[])
{
	int n,a,b,c;
	scanf ("%d",&n);
	a=(n/3600)%24;
	b=(n-n/3600*3600)/60%60;
	c=(n-n/3600*3600-(n-n/3600*3600)/60*60)%60;
	printf("%02d:%02d:%02d\n",a,b,c);
}

C++ :

#include <iostream>  
using namespace std;  
int main(){  
   int n;
   cin>>n;
   int a = n / 3600;
   int b = n % 3600 / 60;
   int c = n % 3600 % 60;
   if(a < 10){ 
      cout<<"0"<<a<<":";
   }else{ 
      cout<<a<<":";
   }
   if(b < 10){ 
      cout<<"0"<<b<<":";
   }else{ 
      cout<<b<<":";
   }
   if(c < 10){ 
      cout<<"0"<<c<<endl;
   }else{ 
      cout<<c<<endl;
   }
   return 0;  
} 

Pascal :

var n,miao,shi,fen:longint;
begin
  readln(n);
  shi:=n div 3600;
  fen:=n mod 3600 div 60;
  miao:=n mod 60;
  if shi div 10=0
    then if fen div 10=0
           then if miao div 10=0
                  then writeln('0',shi,':0',fen,':0',miao)
                  else writeln('0',shi,':0',fen,':',miao)
           else if miao div 10=0
                  then writeln('0',shi,':',fen,':0',miao)
                  else writeln('0',shi,':',fen,':',miao)
    else if fen div 10=0
           then if miao div 10=0
                  then writeln(shi,':0',fen,':0',miao)
                  else writeln(shi,':0',fen,':',miao)
           else if miao div 10=0
                  then writeln(shi,':',fen,':0',miao)
                  else writeln(shi,':',fen,':',miao);
end.

Java :

import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int n=sc.nextInt();
		int h,m,s;
		h=n/3600;
		m=n%3600/60;
		s=n%60;
		if(h<10){
			System.out.print("0"+h+":");
		}else{
			System.out.print(h+":");
		}
		if(m<10){
			System.out.print("0"+m+":");
		}else{
			System.out.print(m+":");
		}
		if(s<10){
			System.out.print("0"+s);
		}
		else{
			System.out.print(s);
		}
	}
}

Python :

n = int(input())
shi = 0
fen = 0
miao = 0
t = 0
# 如果n整除3600大于等于1,则取整赋值给shi,余数赋值给t,t再分两种情况分析,一种是大于等于60,另外就是小于60
if n // 3600 >= 1:
    shi = n // 3600
    t = n % 3600
    #余数大于60的情况
    if t // 60 >= 1:
        fen = t // 60
        miao = t % 60
    #余数小于60的情况
    else:
        miao = t
#n小于3600时
else:
    fen = n // 60
    miao = n % 60
#格式化输出
print('%02d:%02d:%02d' % (shi, fen, miao))