C++day4

1、仿照string类，完成myString 类

#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):str(new char(*other.str)),size(other.size){cout<<"拷贝构造函数"<<endl;}//析构函数~myString(){delete str;cout<<"myString::析构函数:"<<this<<endl;}//拷贝赋值函数myString & operator=(const myString &other){if(this != &other){this->size = other.size;//判断原来的指针空间是否被清空if(this->str != NULL){delete this->str;}this->str = new char(*other.str);}cout<<"myString::拷贝赋值函数"<<endl;return *this;}//判空函数bool my_empty(){if(0 == get_size()){return true;}return false;}//size函数int get_size(){size=0;while(*str != 0){str++;size++;}return size;}//c_str函数char *c_str(){return this->str;}//at函数char &at(int pos){if(pos >= 0 && pos< size){return this->str[pos];}else{cout<<"数组越界"<<endl;}}//加号运算符重载const myString operator+ (const myString &R)const{myString c;c.str=strcat(this->str, R.str);return c;}//加等于运算符重载myString operator+= (const myString &R){//this->str = new char[this->size+R.size+1];strcat(this->str,R.str);this->size+=R.size;return *this;}//关系运算符重载（>）bool operator> (const myString &R)const{if(strcmp(this->str,R.str) > 0){return true;}elsereturn false;}//中括号运算符重载char & operator[](int i){if(i >= 0 && i< size){return this->str[i];}else{cout<<"数组越界"<<endl;}}void display(){cout<<this->str<<endl;}
};
int main()
{myString ptr("hello");myString ptr2("world");myString ptr3 = ptr+ptr2;ptr3.display();cout<<ptr.at(1)<<endl;cout<<ptr[1]<<endl;ptr+=ptr2;ptr.display();return 0;
}