C++ :

#include<iostream>
 using namespace std;
 int main(){
     double n;
     cin >> n;
     int m = n * 10;
     cout << m % 10 << ".";
     m = m / 10;
     cout << m % 10;
     m = m / 10;
     cout << m % 10;
     m = m / 10;
     cout << m % 10;

     return 0;
 }