如何通过重载运算符+=，实现两个字符串的拼接？

Question

#include "MyStringClass.hpp"
MyString::MyString(){
	buff="\0";
}
MyString::MyString(const char *a){
	buff=(char*)a;
}
MyString::MyString(MyString &a){
	buff=a.buff;
}
MyString::~MyString(){}
    
MyString& MyString::operator +=(MyString &a){
	
	return *this;
}
    
int MyString::Length(){
	return strlen(buff);
}
void MyString::toString(){
	cout<<"字符串为："<<buff<<endl;
}
int MyString::Compare(MyString &a){
	return strcmp(buff,a.buff);
}

MyString类中私有成员只有一个char* buff,要重载+=，实现两个MyString类中buff字符串的拼接，如何做到？请写出我这个文件里那个重载+=函数的具体内容

Answer 1

/*
注意，使用到的成员变量如下:
char *string;                    
int length;                       
*/
MyString& MyString::operator +=(MyString &a){

    char *dest;

   dest = new char[str.length+length+1];

   memcpy(dest,string,length);

   memcpy(dest+length,str.string,str.length+1);

   delete[]string;

   length = length+str.length;

   string = dest;

    return *this;

}