Question

I have created a simple program that “draws” shapes within command prompt. I am using several class implementation, but the main issue is within the Command abstract class, more specifically the destructor in that class. I am compiling it with a DEBUG mode that I defined that prints a '-' every time the destructor deletes an object.

The Command class looks something like this:

class Command {
    public:
        Command(){
#ifdef DEBUG
            std::cout << '+';
#endif
        }
        virtual ~Command() {
#ifdef DEBUG
            std::cout << '-';
#endif
        }   
        virtual void execute() = 0;
        virtual void unexecute() = 0;
};

The loop I am calling within another class is as follows:

vector<Command*>  history_;

while(position_ != 0) {
    delete *history_.end();
    history_.pop_back();
    position_--;
}

if position_ is greater than 1 it prints the '-' n – 1 times, but it doesn’t call the destructor on the first delete of the loop.

Answer 1

For an STL container end() does not references the last item, but the place just after the last item.