刚学C++,自己写了个简单的mystring，有警告存在啊，const怎样用呢

C/C++ code

#include <iostream>#include <cstring>//#include "Integer.h"using namespace std;class mystring {private:     char* _s;public:    mystring(int a){ _s = new char[a+1]; for(int i = 0; i < a; i++) _s[i] = ' '; _s[a+1] = '\0'; } /*21*/mystring( char* s  )  { _s = new char[strlen(s)+1]; _s = s; }    mystring( ) { _s = new char[1]; _s[0] = '\0'; }    ~mystring() { delete []_s; }    void display() { cout<<"<"<<_s<<">"<<endl; }};int main(){  mystring s1("sdfgfdgdf");  mystring s2(5);  mystring s3;  s1.display();  s2.display();  s3.display();  s3 = s1;  s3.display();  return 0;}

21行那一行有问题：
\one.cpp|21|warning: deprecated conversion from string constant to 'char*'|

求指教···


[解决办法]
_s = new char[strlen(s)+1];//申请一个长度为……的内存空间，将指针_s指向这个内存空间
_s = s;//将指针_s指向输入的指针s

你刚申请的空间转眼就被掷出窗外了
[解决办法]
_s = new char[strlen(s)+1]; strcpy(_s,s);