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Why do we need virtual functions in C++?
... you're assigning the subclassed object (Cat), the method being invoked is based on the pointer type (Animal) not the type of object it is point to. This is why you need "virtual".
– rexbelia
Feb 7 '16 at 4:08
...
C++静态和多态，亦敌亦友 - C/C++ - 清泛网 - 专注C/C++及内核技术
...遭遇静态函数
#include <iostream>
using namespace std;
class Base
{
public:
virtual void foo(void){ cout << "Base::foo()" << endl; }
};
class Derived : public Base
{
public:
void foo(void){ cout << "Derived::foo()" << endl; }
} ;
class DerivedAgain : public Derived
...
How to call a parent method from child class in javascript?
..., with some tests, you can use it like this, inside your method use : call_base(this, 'method_name', arguments);
It make use of quite recent ES functions, an compatibility with older browsers is not guarantee. Tested in IE11, FF29, CH35.
/**
* Call super method of the given object and method.
* ...
super() in Java
...program 2 proofs our first statement of super() in Java.
Program 1
class Base
{
int a = 100;
}
class Sup1 extends Base
{
int a = 200;
void Show()
{
System.out.println(a);
System.out.println(a);
}
public static void main(String[] args)
{
new Sup1...
How to hide one item in an Android Spinner
...pinner dropdown you need to pass the position of item which needs to hided based on criteria required.
I have achieved this in a use case of hiding the item which is selected from dropdown
public class CustomAdapter extends ArrayAdapter<String> {
private List<String> dates;
private int...
C++ “virtual” keyword for functions in derived classes. Is it necessary?
...Virtual functions
2 If a virtual member function vf is declared in a class Base and in a class Derived, derived directly or indirectly from Base, a member function vf with the same name, parameter-type-list (8.3.5), cv-qualification, and ref-qualifier (or absence of same) as Base::vf is declared, th...
How can I initialize base class member variables in derived class constructor?
...{
B()
{
a = 0;
b = 0;
}
};
You can't access base members in the initializer list, but the constructor itself, just as any other member method, may access public and protected members of the base class.
...
Python class inherits object
... two styles of classes depending on the presence or absence of object as a base-class:
"classic" style classes: they don't have object as a base class:
>>> class ClassicSpam: # no base class
... pass
>>> ClassicSpam.__bases__
()
"new" style classes: they have, directly...
Understanding Python super() with __init__() methods [duplicate]
...
super() lets you avoid referring to the base class explicitly, which can be nice. But the main advantage comes with multiple inheritance, where all sorts of fun stuff can happen. See the standard docs on super if you haven't already.
Note that the syntax changed i...
Clang optimization levels
...asses is available here.
With version 6.0 the passes are as follow:
baseline (-O0):
opt sets: -tti -verify -ee-instrument -targetlibinfo -assumption-cache-tracker -profile-summary-info -forceattrs -basiccg -always-inline -barrier
clang adds : -mdisable-fp-elim -mrelax-all
-O1 is based on -...