c++中string类的常用方法有哪些

c++中string类的常用方法如下：

1、获取字符串长度

  #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：%dnn",length );     return 0; }

2、字符串连接

  #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; }

3、字符串比较

  #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; }

4、字符串转字符数组

  #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; }

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