// Heading
#include <iostream>
#include <string>
using namespace std;


int main ( )
{
    // Declaration
    string s1;
    string s2;
    string s3;
    string s4;
  
    // Assignment
    s1="How old are you ?";
    s2.assign(s1); // or s2=s1;
    s3="I'm fine.";
    s4.assign(s1,8,14);

    // Direct display
    cout << "s1= " << s1 << endl;

    // Declaration of the iterator pos
    string::iterator pos;

    // Display using iterator
    cout << "s1= ";
    for (pos=s1.begin( );pos!=s1.end( );++pos) {
       cout << *pos << " ";
    }
    cout << endl;
   
    // Modify and display s2
    cout << "s2=  " << s2.erase(3,4)<< endl;

    // Modyfy and display s3
    s3=s2 + " " + s3;
    cout << "s3= " << s3 << endl;

    // Modify and display s4
    cout << "s4= " << s4.insert(0,"Who ") << endl;

    // Reverse and display s4
    reverse(s4.begin(),s4.end());
    cout << "new s4= " << s4 << endl;

}