Can I call a base class s virtual function if I m overriding it

Question

Say I have classes Foo and Bar set up like this   class Foo   public      int x       virtual void printStuff                 std  cout  lt  lt  x  lt  lt  std  endl            class Bar   public Foo   public      int y       void printStuff                    I would like to call Foo printStuff   here            std  cout  lt  lt  y  lt  lt  std  endl             As annotated in the code  I d like to be able to call the base class s function that I m overriding  In Java there s the super funcname   syntax  Is this possible in C

User · Answer

Just in case you do this for a lot of functions in your class:

class Foo {
public:
  virtual void f1() {
    // ...
  }
  virtual void f2() {
    // ...
  }
  //...
};

class Bar : public Foo {
private:
  typedef Foo super;
public:
  void f1() {
    super::f1();
  }
};

This might save a bit of writing if you want to rename Foo.

User · Answer

check this      include  lt stdio h gt   class Base   public     virtual void gogo int a    printf   Base    gogo  int   n              virtual void gogo1 int a    printf   Base    gogo1  int   n          void gogo2 int a    printf   Base    gogo2  int   n              void gogo3 int a    printf   Base    gogo3  int   n           class Derived   protected Base   public     virtual void gogo int a    printf   Derived    gogo  int   n          void gogo1 int a    printf   Derived    gogo1  int   n          virtual void gogo2 int a    printf   Derived    gogo2  int   n          void gogo3 int a    printf   Derived    gogo3  int   n                  int main        std  cout  lt  lt   Derived   lt  lt  std  endl     auto obj   new Derived      obj- gt gogo 7      obj- gt gogo1 7      obj- gt gogo2 7      obj- gt gogo3 7      std  cout  lt  lt   Base   lt  lt  std  endl     auto base    Base  obj     base- gt gogo 7      base- gt gogo1 7      base- gt gogo2 7      base- gt gogo3 7       std  string s     std  cout  lt  lt   press any key to exit   lt  lt  std  endl     std  cin  gt  gt  s     return 0      output  Derived  Derived    gogo  int   Derived    gogo1  int   Derived    gogo2  int   Derived    gogo3  int  Base  Derived    gogo  int   Derived    gogo1  int   Base    gogo2  int   Base    gogo3  int  press any key to exit   the best way is using the base  function as say  sth

User · Answer

If you want to call a function of base class from its derived class you can simply call inside the overridden function with mentioning base class name like Foo  printStuff      code goes here   include  lt iostream gt  using namespace std   class Foo   public      int x       virtual void printStuff                  cout lt  lt  Base Foo printStuff called  lt  lt endl            class Bar   public Foo   public      int y       void printStuff                 cout lt  lt  derived Bar printStuff called  lt  lt endl          Foo  printStuff        also called the base class method           int main         Bar  b new Bar      b- gt printStuff        Again you can determine at runtime which function to call using the object of that class derived or base  But this requires your function at base class must be marked as virtual   code below   include  lt iostream gt  using namespace std   class Foo   public      int x       virtual void printStuff                  cout lt  lt  Base Foo printStuff called  lt  lt endl            class Bar   public Foo   public      int y       void printStuff                 cout lt  lt  derived Bar printStuff called  lt  lt endl            int main          Foo  foo new Foo      foo- gt printStuff        this call the base function     foo new Bar      foo- gt printStuff

User · Answer

Yes   class Bar   public Foo                void printStuff                 Foo  printStuff               It is the same as super in Java  except it allows calling implementations from different bases when you have multiple inheritance   class Foo   public      virtual void foo                           class Baz   public      virtual void foo                           class Bar   public Foo  public Baz   public      virtual void foo                Choose one  or even call both if you need to          Foo  foo            Baz  foo

User · Answer

Yes you can call it  C   syntax for calling parent class function in child class is   class child  public parent               void methodName         parent  methodName       calls Parent class  function          Read more about function overriding

User · Answer

Sometimes you need to call the base class  implementation  when you aren t in the derived function   It still works   struct Base       virtual int Foo                 return -1            struct Derived   public Base       virtual int Foo                 return -2            int main int argc  char  argv          Base  x   new Derived       ASSERT -2    x- gt Foo            syntax is trippy but it works     ASSERT -1    x- gt Base  Foo          return 0

User · Answer

The C   syntax is like this   class Bar   public Foo               void printStuff         Foo  printStuff       calls base class  function

User · Answer

If there are multiple levels of inheritance  you can specify the direct base class  even if the actual implementation is at a lower level  class Foo   public    virtual void DoStuff                class Bar   public Foo       class Baz   public Bar   public    void DoStuff            Bar  DoStuff             In this example  the class Baz specifies Bar  DoStuff   although the class Bar does not contain an implementation of DoStuff  That is a detail  which Baz does not need to know  It is clearly a better practice to call Bar  DoStuff than Foo  DoStuff  in case a later version of Bar also overrides this method

[c++] Can I call a base class's virtual function if I'm overriding it?

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