gistfile1.cpp

int length = 100; //value of length can be determined at run-time

int *dyn = new int[length]; //new int[length] returns a pointer to
	                        //first element of the array.

cout << "Using pointers:" << endl;
	
*dyn = 10;		   //dyn[0] and *dyn are equivalent!
*(dyn + 1) = 15; // *(dyn + 1) and dyn[1] are equivalent!

cout << "dyn[0] = " << dyn[0] << endl;
cout << "dyn[1] = " << dyn[1] << endl;

cout << endl;

cout << "Using array index:" << endl;
	
dyn[0] = 20;
dyn[1] = 25;

cout << "dyn[0] = " << dyn[0] << endl;
cout << "dyn[1] = " << dyn[1] << endl;

delete[] dyn;  //the memory must be deallocated.

dyn = NULL;    //trying to use the pointer again 
				//would result in undefined 
				
Output is:
dyn[0] = 10
dyn[1] = 15
dyn[0] = 20
dyn[1] = 25