C++- pointer reference and dereference

Objective

• pointier basics:
  • pointer is classified under derived data type, along with array and reference
  • indirection pointer :  *
    • dereference pointer:  (also know as structure pointer operator)
       -> ( member selection(pointer)
      ( example structure_object->member_variable = 10;  )
      This will set reference to the class . The same can be acheived with DOT operator with (----) .
      (structure_object)member_variable = 10;
    • DOT operator
      structure_object.member_variable = 10 ;
      this directs to member_variable, since DOT precedes INDIRECTION operator, the pointer will try to deference the member_variable than the structure_object. 
  • indirection and address of operators :  *&
  • these pointers are unary type, meaning that these would appear in front of the operand like *n1, &p1 or classobject->variable = 10;
• pointer to integer data type

A pointer is actually holds an address of variable in the computer memory.

• reference operator  "&"  also known as address of operator.
• indirection operator "*" also known as "value pointed by" : this allows to access a value through a pointer. (This is different from multiplication *  operator ) .
• deference operator -> ( myPointerToClass1.htm )

"from -CPP Essentials-->A pointer is simply the address of an object in memory. Generally, objectscan be accessed in two ways: directly by their symbolic name, or indirectly througha pointer. The act of getting to an object via a pointer to it, is called dereferencingthe pointer. Pointer variables are defined to point to objects of a specific type sothat when the pointer is dereferenced, a typed object is obtained."

 

#include <iostream>
#include <stdio.h>
#include <fstream>
using namespace std;
//pointer_1.cpp
//size_t fread ( void * ptr, size_t size, size_t count, FILE * stream );
int main()
{
int * p1, * p2;
int n1, n2;
p1 = &n1;
*p1 = 20;
p2 = &n2;
*p2 = 50;
cout << "value of n1 " << n1 << " Value of n2 " << n2 <<endl;
cout << "address of n1 " << &n1 <<endl; cout<< "address of p1 " << p1;
return 0;
}