#include <iostream>
using namespace std;


void test01 ()
{
    string s1 = "我";
    s1 += "爱玩游戏";
    cout << s1 << endl;

    s1 += ':';

    string s2 = "lol dnf";
    s1 += s2;
    cout << s1 << endl;

    string s3 = "i";
    s3.append("love game");
    cout << s3 << endl;
    
    s3.append("game abced", 4);

    s3.append(s2);
    cout << s3 << endl;

    s3.append(s2, 0, 3);


}

int main ()
{
    test01();

    return 0;
}