C++ string（初始化和部分函数的使用）

#include<string>#include<stdlib.h>#include<stdio.h>#include<iostream>using namespace std;int main(){    //string 初始化    string s1 = "ywb";    string s2(s1);    string s3 = s2;    string s4("yangwen");    string s5(10, 'c');    cout << s1 << " " << s2 << " " << s3 << " " << s4 << " " << s5 << endl;    //string 一部分函数的使用    string str("yangwenbin");    int length = str.length();//求取字符串长度    int length1 = str.size(); //求取字符串长度    cout << length << "　" << length1 << endl;    for (int i = 0; i < length1; i++)    {        cout << str.at(i) << " " ;  //返回字符串第i个位置的字符    }    cout << endl;    cout << *str.begin() << endl;   //返回字符串的首字符    cout << *(str.end() - 1) << endl;; //返回字符串的尾元素    if (!str.empty())  //判断字符串是否为空    {        cout << "i am not empty" << endl;;    }    str.resize(length + 10, 'a'); //重新分配空间，将多余的十个空间分配a    cout << str << endl;;    str.clear(); //清除字符串    if (str.empty())  //判断字符串是否为空    {        cout << "i am empty" << endl;;    }    str.append("ywb");    cout << str << endl;    str.append(" hell0");//append 在string后插入字符串    cout << str;    system("pause");}