typedef is a language construct that associates a name to a type.You use it the same way you would use the original type, for instance using them like As you can see, you could just replace the typedefed name with its definition given above. The difficulty lies in the pointer to functions syntax and readability … Read more
A cast, as Blaz Bratanic suggested: is likely to silence the warning (though in principle a compiler can warn about anything it likes, even if there’s a cast). But it doesn’t solve the problem that the warning was telling you about, namely that a conversion from size_t to int really could overflow. If at all … Read more
How do you handle a “cannot instantiate abstract class” error in C++? I have looked at some of the similar errors here and none of them seem to be exactly the same or problem that I am having. But, then again, I will admit that there are several to go over. Here is the compile … Read more
Move doSomething definition outside of its class declaration and after B and also make add accessible to A by public-ing it or friend-ing it.
The two int variables are defined in the header file. This means that every source file which includes the header will contain their definition (header inclusion is purely textual). The of course leads to multiple definition errors. You have several options to fix this. Make the variables static (static int WIDTH = 1024;). They will … Read more
You have to properly understand what is a “stdafx.h”, aka precompiled header. Other questions or Wikipedia will answer that. In many cases a precompiled header can be avoided, especially if your project is small and with few dependencies. In your case, as you probably started from a template project, it was used to include Windows.h … Read more
Your problem is here: You’re not creating an instance of ElemAlg, so you’re calling a member function on an uninitialized pointer. Because the member function you are calling isn’t virtual the compiler won’t have to do any runtime lookup, which is why the call goes to GetQuiz. However, the this pointer will be garbage (as ea is uninitialized), so the moment … Read more
When you pass a pointer by a non-const reference, you are telling the compiler that you are going to modify that pointer’s value. Your code does not do that, but the compiler thinks that it does, or plans to do it in the future. To fix this error, either declare x constant or make a … Read more
What does this mean? tools.cpp(107): tools.h(52)
You forgot the return types in your member function definitions: and so on.