c++中string类的常用方法有哪些

#include<cstdio>

#include<iostream>

#include<string>

using namespace std;

int main()

{

    string str1 = "hello";

    int length = str1.length();

    printf("调用str.length()函数获取字符串长度：%d\n\n",length );

    return 0;

}

#include<cstdio>

#include<iostream>

#include<string>

using namespace std;

int main()

{

    string str1 = "hello";

    string str2="my girl!";

    string str3="hello ";

    string str4=str1+str2;

    string str5=str3+str2;

    cout<<"字符串str1+str2连接结果："<<str4<<endl;

    cout<<endl;

    cout<<"字符串str3+str2连接结果："<<str5<<endl;

    return 0;

}

#include<cstdio>

#include<iostream>

#include<string>

using namespace std;

int main()

{

    string str1 = "hello";

    string str2="my girl!";

    string str3="hello ";

    if (str1 < str3)

        cout << "字符串比较结果：" << "str1<str2" << endl;

    cout << endl;

    return 0;

}

#include<cstdio>

#include<iostream>

#include<string>

#include<cstring>

using namespace std;

int main()

{

    string str1 = "hello";

    string str2="my girl!";

    string str3="hello ";

    char *d = new char[20];  //因为下一句那里不是直接赋值，所以指针类型可以不用const char *

    strcpy(d, str3.c_str());  //c_str 取得C风格的const char* 字符串

    cout << "str3:" << c << endl;

    cout << "d:" << d << endl;

    str3 = "hahaha";

    cout << "str3:" << c << endl;

    cout << "d:" << d << endl;

    return 0;

}