5/6課輔-字串的長度、大小

//字串的長度、大小
#include <iostream>
#include <string>
using namespace std;

int main()
{
    string s1="this is s1";
    cout<<s1[2]<<endl;
    cout<<"length():"<<s1.length()<<endl;
    cout<<"size():"<<s1.size()<<endl;
    cout<<"sizeof():"<<sizeof(s1)<<endl;
    return 0;
}