5/6課輔-字串的基本宣告、定義、組合

//字串的基本宣告、定義、組合
#include <iostream>
#include <string>
using namespace std;

int main()
{
    string s1;
    s1="this is s1";
    string s2="this is s2";
    string s3="this is";
    s3=s3.append(" s3");
    string s4="this is";
    s4+=" s4";
    cout<<s1<<endl<<s2<<endl<<s3<<endl<<s4<<endl;
    return 0;
}