String to int and Int to string c++

#include <iostream>

#include <string>

#include <sstream>

using namespace std;

int main()

{

stringstream ss;

// string to int

string str="12";

ss<<str;

int a;

ss>>a;

cout<<a<<"\n";

//int to string

ss<<a;

string str1;

ss>>str1;

cout<<str1<<" ";

return 0;

}