运算符重载

将昨天的My_string类中的所有能重载的运算符全部进行重载

+、[] 、>、<、==、>=、<=、!= 、+=（可以加等一个字符串，也可以加等一个字符）、输入输出(<< 、 >>)

#include <iostream>
#include <string.h>
using namespace std;class My_string
{
private:int len;int size;char *ptr;
public:My_string():size(15),len(0){ptr=new char[size];ptr[0]='\0';}My_string(const char *src){len = strlen(src);ptr = new char[len+1];strcpy(ptr,src);}My_string(const My_string& other):ptr(new char[this->len]),len(other.len){len = other.len;size = other.size;ptr = new char[size];strcpy(ptr,other.ptr);}//拷贝赋值My_string& operator=(const My_string& other){if(this!=&other){delete[]ptr;len = other.len;size = other.size;ptr = new char[size];strcpy(ptr,other.ptr);}return *this;}//析构函数~My_string(){delete[]ptr;}//判空bool empty(){return this->len==0;}//尾插void push_back(char x){if(this->len==this->size-1){return ;}this->ptr[len++]=x;}//尾删void dele_back(){if(this->len==0){return ;}this->ptr[len-1]=this->ptr[len];this->len--;}//at函数实现char &at(int x){if(x>=0&&x<size){return ptr[x];}else{cout<<"超出范围"<<endl;exit(1);}}//清空函数void dele_empty(){for(int i=0;i<this->len;i++){dele_back();}}//返回C风格字符串char *my_ptr(){return this->ptr;}//返回实际长度int my_len(){return this->len;}//返回当前最大容量int my_size(){return this->size;}//二倍扩容void doubledilatation(){//char *ptr1=new char[size];//*ptr1=*this->ptr;// if(this->len==this->size)// {//      this->size*=2;// }// cout <<" len="<<len<<"   size="<<size<<endl;size *= 2;char *new_ptr = new char[size];strcpy(new_ptr, ptr);delete[] ptr;ptr = new_ptr;}void show(){cout <<"len="<<len<<"    size="<<size<<"   ptr="<<ptr<<endl;}
};
class Complex
{
private:int left;int right;string a;
public:Complex(){};Complex(int l,int r):left(l),right(r){};const Complex operator +(const Complex& R)const{Complex temp;temp.right=this->right+R.right;temp.left=this->left+R.left;return temp;}bool operator <(const Complex &R)const{return this->left<R.left&&this->right<R.right;}bool operator >(const Complex &R)const{return this->left>R.left&&this->right>R.right;}bool operator ==(const Complex &R)const{return this->left==R.left&&this->right==R.right;}bool operator <=(const Complex &R)const{return this->left<=R.left&&this->right<=R.right;}bool operator >=(const Complex &R)const{return this->left>=R.left&&this->right>=R.right;}bool operator !=(const Complex &R)const{return this->left!=R.left||this->right!=R.right;}Complex &operator +=(const Complex &R){this->left+=R.left;this->right+=R.right;return *this;}Complex &operator +=(const std::string &R){this->a+=R;return *this;}friend ostream &operator <<(ostream &L,const Complex &R);friend istream &operator >>(istream &L,Complex &R);void show(){if(right<0){cout<<this->left<<this->right<<endl;}else{cout<<this->left<<"+"<<this->right<<endl;}}
};
ostream &operator <<(ostream &L,const Complex &R)
{if(R.right<0){L<<R.left<<R.right<<endl;}else{L<<R.left<<"+"<<R.right<<endl;}return L;
}
istream &operator >>(istream &L,Complex &R)
{L>>R.left>>R.right;return L;
}int main()
{My_string s1;My_string s2("lili");My_string s3("lililyq");My_string s4(s2);My_string s5(s2);s2.push_back('y');s2.show();s2.dele_back();s2.show();cout<<"第一个字符："<<s2.at(2)<<endl;cout<<s2.my_ptr()<<endl;cout<<s2.my_len()<<endl;cout<<s2.my_size()<<endl;//while(1)// {//    s2.doubledilatation();//}Complex a1(15,6);a1.show();Complex a2(5,-1);Complex a3=a1+a2;a3.show();return 0;
}