Pointers Usage in C++: Beginners to Advanced

#include <iostream>

using namespace std;

int i = 0;

int *ptr1;

int main ()
{
 	ptr1 = new int;
	/*
		 'new' allocates memory for an unnamed integer. The base memory address of the variable is then assigned to ptr1. We can freely access the unnamed variable through the pointer.
	*/
	*ptr1 = 10;

	*ptr1 = 2 + *ptr1;

	cout << "Dynamic memory allocation: Value of ptr1 is " << *ptr1 << "\n";

	
 	/*
		Free up allocated memory by dereferencing. Use the pointer once more by assigning it another memory address.
	*/
	delete ptr1;

	
	/*
		Same pointer is now allocated the base address of an array
	*/
	ptr1 = new int[3];


	/*
		The unnamed array can be easily accessed using the pointer ptr1. There is more than one way to do this.
	*/
	*(ptr1+0)=2;
 	*(ptr1+1)=4;
	ptr1[2]=6;

	
	cout << "Printing array of pointers: \n";
	for(i=0;i<3;i=i+1)
	{
		cout << "*(ptr1+" << i << ") = " << *(ptr1+i) << "\n";		
	}

	
	/*
		Note that array notation is used to access pointer.
	*/
	cout << "Reprinting array of pointers: \n";
	for(i=0;i<3;i=i+1)
	{
		cout << "ptr1[" << i << "] = " << ptr1[i] << "\n";
	}
	
	
	/*
		Free up memory by dereferencing the pointer. Array size need not be specified. Deleted memory is returned to free store.
	*/
	delete[ ] ptr1;
	
	
	return (0);
}