overriding

This question already has an answer here: vector of objects 5 answers class classa { public: virtual void foo(); }; class classb : public classa { public: virtual void foo() override; }; void classa::foo() { std::cout << "foo from a" << std::endl; } void classb::foo() { std::cout << "foo from b" << std::endl; } int main() { std::vector<classa> stuff; classa a; classb b; stuff.push_back(a); stuff.push_back(b); stuff[0].foo(); stuff[1].foo(); return 0; } I expected the above code to return foo from a foo from b but it returns both as foo from a . I think this is because the vector stores classa

Is it possible to pass in a bool variable into an overridden toString() method, so it can conditionally print the object in different formats? You can define overload method of ToString() . public string ToString(bool status){ // } The typical pattern for parametrized ToString() is to declare an overload with a string parameter. Example: class Foo { public string ToString(string format) { //change behavior based on format } } For a framework example see Guid.ToString If you are talking about your own class, you could do the following: public class MyClass { public bool Flag { get; set; }

Did I dream this? I could have swore I read something about java 7 supplying an annotation that you could place on a method to ensure all subclasses call super. Has this been renamed, or dropped, or was it never actually considered? It was part of JSR 305: Annotations for Software Defect Detection and called @OverridingMethodsMustInvokeSuper . The JSR is inactive, but a reference implementation is available bundled with FindBugs It could have been suggested for project Coin, which accepted many suggested but picked the best/simplest of the list. You can do this instead. public final void

Ok, I have a rails gem that I am working on and I want it to override a specific method in sprockets. The method I want to override is: Sprockets::Base.digest so that I can base the fingerprint off my gem version when compiling the app's assets. How would I go about doing that? In my gem I create a file lib/sprockets/base.rb and place the following code: class Sprockets::Base def digest @digest = digest_class.new.update(MyGem::VERSION) @digest.dup end end When I run bundle exec rake assets:precompile I get: undefined method 'logger=' for #<Sprockets::Environment:0x1315b040> So it almost seems

As I write on title, I hope to show mouse position like tooltip. To do that, I think that I have to override QCursor, right? But I don't know the details of QCursor and how to make a new cursorShape. Is there any example like this? Assuming you want a coordinate readout as you move the cursor (like in many graphics or CAD applications), you really do not want to override QCursor . The most efficient approach depends on what widget will be providing the coordinates, but in most cases the simplest way will be to setMouseTracking(true) for the widget, and override it's mouseMoveEvent(QMouseEvent*