仿照string类，完成myString 类

代码：

#include <iostream>
#include <cstring>
using namespace std;
class myString
{private:char *str;          //记录c风格的字符串int size;            //记录字符串的实际长度public://无参构造myString():size(10){str = new char[size];         //构造出一个长度为10的字符串strcpy(str,"");         //赋值为空串}//有参构造myString(const char *s)          //string  s("hello world"){size = strlen(s);str = new char[size+1];strcpy(str, s);}//拷贝构造myString(const myString &other){size=other.size;str= new char[size];strcpy(str,other.str);}//析构函数~myString(){delete[] str;}//拷贝赋值函数myString & operator=(const myString &other){if(this != &other)          //确定不是自己给自己赋值{this->size = other.size;//判断原来指针空间释放被清空if(this->str != NULL){delete this->str;}this->str = new char(*other.str);}cout<<"拷贝赋值函数"<<endl;return  *this;             //返回自身引用}//判空函数bool string_empty(){return size==0;}//size函数unsigned long long int string_size(){return strlen(str);}//c_str函数const char* c_str(const myString s1){char *p=new char[s1.size+1];strcpy(p,s1.str);return p;}//at函数char &at(int pos){if(pos>=0&&pos<this->size){return str[pos];}else{cout<<"数据输入错误"<<endl;return str[0];}}//加号运算符重载const  myString  operator+ ( const myString &R)const{myString s;s.size = this->size + R.size;strcpy(s.str,this->str);strcat(s.str,R.str);return s;}//加等于运算符重载myString & operator+=(const myString &R){this->size += R.size;strcat(this->str,R.str);return *this;                //返回自身的引用}//关系运算符重载（>）bool operator>(const myString &R)const{if(strcmp(this->str,R.str)>0){return 1;}else{return 0;}}//中括号运算符重载char & operator[](int index){return this->str[index];}};
int main()
{myString s1("hello");string s2="world";string s3="war";myString s4("world");cout<<s1.string_size()<<endl;cout<<s1.at(2)<<endl;s2+=s3;cout<<s2<<endl;cout<<s2+s3<<endl;if(s1 > s4)              //调用关系运算符重载函数{cout<<"yes"<<endl;}else{cout<<"no"<<endl;}return 0;
}

运行结果：

思维导图