自己封装类似C++中的string类

Mystring.h

#ifndef MYSTRING_H
#define MYSTRING_H
#include <iostream>
#include<string.h>
using namespace std;class myString
{friend ostream& operator<<(ostream &cout,const myString &s);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 &s);//析构函数~myString();//拷贝赋值函数myString& operator=(const myString &s);//判空函数bool empty()const;//size函数int strsize() const;//c_str函数const char* c_str() const;//at函数char &at(int pos) const;//加号运算符重载const myString operator+(const myString &rstr) const;//加等于运算符重载myString& operator+=(const myString &rstr);//关系运算符重载（>）bool operator>(const myString &rstr) const;//中括号运算符重载char& operator[](const int pos) const;};
void emp(const myString &s);
#endif // MYSTRING_H

Mystring.cpp

#include"Mystring.h"
void emp(const myString &s)
{if(s.empty())cout<<"为空"<<endl;elsecout<<"不为空"<<endl;
}
//<<重载
ostream& operator<<(ostream &cout,const myString &s)
{cout << s.str;return cout;
}//拷贝构造
myString::myString(const myString &s):str(new char(s.size)),size(s.size)
{for(int i = 0;i<s.size;i++){*(this->str+i) = *(s.str + i);}}
//析构函数
myString::~myString()
{if(str != nullptr)delete str;cout<< "析构函数"<<endl;
}
//拷贝赋值函数
myString& myString::operator=(const myString &s)
{if(this->str!=nullptr)delete this->str;this->str = new char (s.size);for(int i = 0;i<s.size;i++){*(this->str+i) = *(s.str+i);}this->size = s.size;return *this;}
//判空函数
bool myString::empty()const
{if(strlen(this->str) == 0)return true;return  false;
}
//size函数
int myString::strsize() const
{return strlen(this->str);
}
//c_str函数
const char* myString::c_str() const
{return this->str;
}
//at函数
char& myString::at(int pos) const
{if(pos<0 || pos > size)throw myString("越界！");return *(this->str+pos);
}
//加号运算符重载
const myString myString::operator+(const myString &rstr) const
{int newsize = this->size+rstr.size;char s[newsize];strcpy(s,this->str);strcat(s,rstr.str);return myString(s);
}
//加等于运算符重载
myString& myString::operator+=(const myString &rstr)
{char *p = this->str;int psize = this->size;this->str = nullptr;this->str = new char (psize+rstr.size);strcpy(this->str,p);delete p;strcat(this->str,rstr.str);return *this;
}
//关系运算符重载（>）
bool myString::operator>(const myString &rstr) const
{if(strcmp(this->str,rstr.str)>0)return true;return false;
}
//中括号运算符重载
char& myString::operator[](const int pos) const
{if(pos>=0&&pos<size)return *(this->str+pos);throw myString("越界！");
}

main.cpp

#include"Mystring.h"
void emp(const myString &s)
{if(s.empty())cout<<"为空"<<endl;elsecout<<"不为空"<<endl;
}
//<<重载
ostream& operator<<(ostream &cout,const myString &s)
{cout << s.str;return cout;
}//拷贝构造
myString::myString(const myString &s):str(new char[s.size]),size(s.size)
{for(int i = 0;i<s.size;i++){*(this->str+i) = *(s.str + i);}}
//析构函数
myString::~myString()
{if(str != nullptr)delete[] str;cout<< "析构函数"<<endl;
}
//拷贝赋值函数
myString& myString::operator=(const myString &s)
{if(this->str!=nullptr)delete[] this->str;this->str = new char [s.size];for(int i = 0;i<s.size;i++){*(this->str+i) = *(s.str+i);}this->size = s.size;return *this;}
//判空函数
bool myString::empty()const
{if(strlen(this->str) == 0)return true;return  false;
}
//size函数
int myString::strsize() const
{return strlen(this->str);
}
//c_str函数
const char* myString::c_str() const
{return this->str;
}
//at函数
char& myString::at(int pos) const
{if(pos<0 || pos > size)throw myString("越界！");return *(this->str+pos);
}
//加号运算符重载
const myString myString::operator+(const myString &rstr) const
{int newsize = this->size+rstr.size;char s[newsize];strcpy(s,this->str);strcat(s,rstr.str);return myString(s);
}
//加等于运算符重载
myString& myString::operator+=(const myString &rstr)
{char *p = this->str;int psize = this->size;this->str = nullptr;this->str = new char (psize+rstr.size);strcpy(this->str,p);delete[] p;strcat(this->str,rstr.str);return *this;
}
//关系运算符重载（>）
bool myString::operator>(const myString &rstr) const
{if(strcmp(this->str,rstr.str)>0)return true;return false;
}
//中括号运算符重载
char& myString::operator[](const int pos) const
{if(pos>=0&&pos<size)return *(this->str+pos);throw myString("越界！");
}