Question

I have this class:

class Base{
     private:
        char *message;
     public:
        Base(string message`);
        ~Base();    
};

Edited: sorry, i forgot giving my constructor!
When i implement the destructor like below:

Base::Base(string message1){
     message = new char[message1.size() + 1]
     message[message1.size()] = '\0';
     memcpy(message, message1.c_str(), message.size());
}
Base::~Base(){
     delete message;  
}

sometime the system go wrong with stop working error, but if instead of delete message, i use message = NULL, everything will be alright! So, if I just declare message = NULL in my destructor, does my program get memory leak?

Answer 1

There’s absolutely no reason to use new here. The constructor takes a std::string and then manually copies its contents into a new dynamically allocated array of char. This is completely worthless. If instead, the constructor simply copied it into another std::string, the std::string copy constructor would do the same, but with lots of free benefits: exception-safety, no memory leaks, and proper copy semantics.

class Base{
     private:
        string message;
     public:
        Base(string message);
        // maybe a virtual destructor is desirable if this is a polymorphic base class
        // virtual ~Base() {}
};

Base::Base(string message1) : message(message1) {}