C :

#include<stdio.h>
#include<string.h>
int main(){
	char s[255];
	gets(s);
	int i;
	for(i=strlen(s)-1;i>=0;i--){	
	printf("%c",s[i]);
}
	return 0;
}

C++ :

#include<bits/stdc++.h>
using namespace std;  
int main(){           
    string s;
    int i;
    getline(cin,s);
	for(i = s.length() - 1;i >= 0;i--)
	{
		cout<<s[i];
	}
	return 0;
}

Pascal :

program ex_1120;
var
  i:integer;
  a:array [1..15] of char;
procedure try(t:integer);
  begin
    if t=15 then write(a[t])
            else
              begin
                try(t+1);
                write(a[t]);
              end;
              end;
begin
  for i:=1 to 15 do read(a[i]);
  try(1);
end.

Java :

import java.util.Scanner;

public class Main {
public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);
	String a = sc.nextLine();
	String s="";
	for(int i=a.length()-1;i>=0;i--){
		s=s+a.charAt(i);
	}
	System.out.println(s);
}
}

Python :

a=input()
b=[]
for i in a:
  b.append(i)
i=len(b)-1
while i>=0:
  print(b[i],end="")
  i=i-1