听侯捷老师讲课的笔记：

string.h头文件：

#pragma onceclass String{public:    String(const char* cstr);    String(const String& str);    String& operator =(const String& str);    ~String();        char* get_c_str() const { return m_data; }//这个类的成员函数内的所有操作，不准备改变私有数据m_data，所以要加上                                              //const去修饰这个函数，一出手就要：不同凡响private:    char* m_data;};inline String::String(const char* cstr=0){    if (cstr)    {        std::cout << "如果传进来的字符串不为空,它就是："<
      
       std::ostream& operator <<(std::ostream& os, const String& str){    os << str.get_c_str();    return os;}
      

string.cpp源文件：

#define _CRT_SECURE_NO_WARNINGS#include
      
       #include"string.h"using namespace std;int main(){        String str("Greetings!,china!");    cout <<"str:  "<< str << endl;        cout << endl;    String* p = new String("hello,world!");    cout << "*p:  " << *p << endl;    delete p;    cout << endl;    String str1("to be or not to be");    cout << "str1:  " << str1 << endl;        cout << endl;    String str2("to be or not to be");    cout << "str2:  " << str2 << endl;    cout << endl;    String str3;    str3 = str2;    cout << "str3:  " << str3 << endl;    cout << endl;    cout << "在做自我赋值str3 = str3之后：" << endl;    str3 = str3;    cout << "str3:  " << str3 << endl;    system("pause");    return 0;}