**Program to find the sum of either of the diagonals of a 4 x 4 matrix** **#include <iostream.h>**

#include <conio.h>

void main()

{

clrscr();

int x;

int A[4][4],sum=0; //Reading the matrix.

cout << "Enter the elements of the matrix : " << endl;

for(int y=0;y<4;y++)

for (int x=0;x<4;x++)

{

cout << "Element " << x+1 << ", " << y+1 << " : ";

cin>>A[x][y];

}

//Sum of either of the diagonal elements.

for(x=0;x<4;x++)

for(y=0;y<4;y++)

if(x==y)

sum+=A[x][y];

else if(y==4-(1+1));

sum+=A[x][y];

cout << "Sum of either of the diagonal elements is : " << sum;

getch();

}

This program takes in the elements A[x][y] of the 4 x 4 matrix as a screen input from the user.

It then calculates the sum of either of its diagonals and outputs it using the 'cout' command.

**Sample Input**

**1**

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

**Sample Output**

**Sum of either of the diagonal elements is : 34**