Answers for "what is pointer in cpp"

pointer in c++

// Variable is used to store value
int a = 5;
cout << a; //output is 5

// Pointer is used to store address of variable
int a = 5;
int *ab;
ab = &a; //& is used get address of the variable
cout << ab; // Output is address of variable

pointers c++

// pointer to functions
#include <iostream>
using namespace std;

int addition (int a, int b)
{ return (a+b); }

int subtraction (int a, int b)
{ return (a-b); }

int operation (int x, int y, int (*functocall)(int,int))
{
  int g;
  g = (*functocall)(x,y);
  return (g);
}

int main ()
{
  int m,n;
  int (*minus)(int,int) = subtraction;

  m = operation (7, 5, addition);
  n = operation (20, m, minus);
  cout <<n;
  return 0;
}

what is this pointer in c++

Every object in C++ has access to its own address through an important pointer called this pointer.
 The this pointer is an implicit parameter to all member functions. 
Therefore, inside a member function,
 this may be used to refer to the invoking object.

Friend functions do not have a this pointer,
 because friends are not members of a class. 
Only member functions have a this pointer.

pointer in cpp details

#include <iostream>
using namespace std;
class Demo {
private:
  int num;
  char ch;
public:
  void setMyValues(int num, char ch){
    this->num =num;
    this->ch=ch;
  }
  void displayMyValues(){
    cout<<num<<endl;
    cout<<ch;
  }
};
int main(){
  Demo obj;
  obj.setMyValues(100, 'A');
  obj.displayMyValues();
  return 0;
}