Write a C++ program to create a new string using two given strings s1, s2, the format of the new string will be s1s2s2s1

#include <iostream>
using namespace std;

string test(string s1, string s2)
         {
            return s1 + s2 + s2 + s1;
         }
        
       
int main() 
 {
  cout << test("Hi", "Hello") << endl;  
  cout << test("whats", "app") << endl;  
  return 0;    
}