Universal character type conversion to int, int to string, string to char or char *, etc.

std :: namespace std can not write a using;
std :: cout can be used alone

#include <iostream>     // std::cout, std::right, std::endl
#include <iomanip>   
#include<sstream>   // std::setw
using namespace std;

int main () {
  int val = 65; 
  
  string s1;
  stringstream ss;
  ss<<val;   //int ->string
  ss>>s1;
  s1+="123";
    cout<<s1;
    ss.clear();
    
    
    int a;
    ss<<s1;    //string->int 
    ss>>a;
    cout<<endl<<a+10000;
    
    ss.clear();
    char cc[10];
    ss<<s1;
    ss>>cc;   //string->char *
    cout<<cc<<endl;
 
    ss.clear();
    string s2;

    ss<<cc;
    ss>>s2;
        s2+="12sda2sd";
    cout<<s2<<endl; 
  return 0;
}