// arr1.cpp 	By: Aiman Hanna - ©1993-2006 Aiman Hanna

// This program introduces arrays, and illustrates how they can be manipulated. 

// Key Points: 	1) Arrays always start with index "0", and go up to the array size - 1.
//		   For example, the indices of an array of 6 elements go from index 0
//		   to index 5. 

#include <iostream.h>

void ArrConstruct()
{
// this function illustrates how arrays are created and manipulated.
// The function creates an array of 6 integers, initializes it, then 
// manipulates it.

int firstarr[ 6 ];	// "firstarr" is the name of the array. "6" here is the 
		// number of indices. 

// Initialize the array. Notice that the array starts always with a "0" index
// and it ends with the number of indices- 1, which is 5 in our example. 

firstarr[0] = 2;
firstarr[1] = 4;
firstarr[2] = 6;
firstarr[3] = 12;
firstarr[4] = 15;
firstarr[5] = 17;

// Show out all the values in the array

cout << "\n Here are the array values after initialization" << endl;
cout << " ===============================================" << endl;
for (int i = 0; i < 6; i++)
	cout << firstarr[i] << "\t";

// Change the values of the 3rd & 5th elements. Notice that since the array starts 
// always with a 0 index, the 3rd element is the one with index # 2, and the fifth 
// element is the one with index # 4

firstarr[2] = 90;	// 3rd element
firstarr[4] = 200;	// 5th element

cout << "\n Here are the array values after 1st modification" << endl;
cout << " =================================================" << endl;

for ( i = 0; i < 6; i++)
	cout << firstarr[i] << "\t";

// Allow the user to change the values of the 1st and 4th elements

cout << "\n Enter two integers: ";
cin >> firstarr[0] >> firstarr[3];

cout << "\n Here are the array values after 2nd modification" << endl;
cout << " =================================================" << endl;

for ( i = 0; i < 6; i++)
	cout << firstarr[i] << "\t";

// Find the total of the values in the array
int totalval = 0;

for ( i = 0; i < 6; i++)
       totalval += firstarr[i];	
cout << "\n The total of the values inside the array is: " << totalval << endl; 

}



int main()
{

ArrConstruct();

return 0;
}


// The output of the program
/*

 Here are the array values after initialization
 ===============================================
2       4       6       12      15      17
 Here are the array values after 1st modification
 =================================================
2       4       90      12      200     17
 Enter two integers: 20 89

 Here are the array values after 2nd modification
 =================================================
20      4       90      89      200     17
 The total of the values inside the array is: 420

*/