Why won't this compile?

Question

https://code.sololearn.com/cYVz13DU1DZ3/#cpp

I've got a header file here and when I instantiate a Compare class object in the main.cpp it does not compile and treats it as an abstract class even though I've implemented the definitions in the source.
Any ideas?

Answer 1

What's your main function look like?

Answer 2

I just put this in main and that's when I get the error

int main()
{
Compare obj1("Chris",5);
}

Just passing in parameters to the constructor

Answer 3

Because of the virtual functions in Compare. Remove the virtual key word.