CODE EXAMPLE FOR CPP

Pointers c++

// This will explain how pointers are used
#include <iostream> 
using namespace std; 
int main() 
{     
  int a = 5;  //Declare and initialize a variable
  /*
  The following pointer declarations are all valid and they all are doing the same:
  Declaring a new pointer and initializing it with 0 (a non accessible memory address) for safety-reasons.
  int * b = 0;
  int* b = 0                 
  int *b = 0; // This is how its usually written.
  int *b; // <= this, however would cause "b" to point to some random address which might be unsafe.
  */
  int *b = 0; // Create a new pointer of type int and initialize it with 0

  cout << ""b" is initialized and now pointing to memory-address:  " << b << endl << endl;

  //Now make the pointer "point" to the address of a
  b = &a; //"b" now points to the address of "a"

  cout << ""a" is stored at memory-address:  " << &a << endl;
  cout << ""b" is stored at memory-address:  " << &b << endl;
  cout << ""b" is pointing to memory-address now:  " << b << endl << endl;

  cout << "The value of "a" is: " << a << endl;  // returns the value of a

  //the "*b" will get the value from the address b points to (the value of a)
  cout << "The value of the area "b" is pointing to is: " << *b << endl << endl << endl;

  //Now modify the value of the address "b" is pointing to...effectively changing the value of "a"     
  *b=10;

  cout << ""a" is still stored at memory-address:  " << &a << endl;
  cout << ""b" is still stored at memory-address:  " << &b << endl;
  cout << ""b" is still pointing to memory-address:  " << b << endl << endl;

  cout << "The value of "a" is now: " << a << endl;  // returns the value of a
  cout << "The value of the area "b" is pointing to is now: " << *b << endl << endl;

  return 0;        
}