#include<iostream>

using namespace std;

//========================================

int main()

{

    string str1="I like C++";

    string str2=",I like the world.";

    string str3="Hello";

    string str4("Hi");

    //====================================

    str1.append(str2);

    str3.append(str2, 11, 7);

    str4.append(5, '.');

    //====================================

    cout<<str1<<endl;

    cout<<str3<<endl;

    cout<<str4<<endl;

    system("pause");

    return 0;  

}