Find Sum of Diagonal Elements of Matrix Program in C++

C++ Program to Find Sum of Diagonal Elements of Matrix

Using this code we find the sum of diagonal elements of a square matrix.For example, for a 2 x 2 matrix, the sum of diagonal elements of the matrix {1,2,3,4} will be equal to 5.

To write this code is same as the sum of elements of a matrix, we add only those elements of the matrix for which row number and column number is same, like 1st row and 1st column, 2nd row and 2nd column and so on(i==j).

1    2

3    4

Sum = 1+4 = 5

Considering 3X3 matrix

• We have to add a[0][0],a[1][1],a[2][2]
• By Observing, it is clear that when i = j Condition is true then and then only we have to add the elements

#include<stdio.h>
#include<conio.h>

void main()
{

   int i, j, matrix[10][10], row, col;
   int sum = 0;
   clrscr();

   cout<<"\nEnter the number of Rows : ";
   cin>>row;
 
   cout<<"\nEnter the number of Columns : ";
   cin>>col;
 
   //Accept the Elements in m x n Matrix
   for (i = 0; i < row; i++) 
   {
      for (j = 0; j < col; j++) 
	  {
         cout<<"\nEnter the Element a[%d][%d] : ", i, j;
         cin>>matrix[i][j];
      }
   }
 
  //Addition of all Diagonal Elements
  for (i = 0; i < row; i++) 
  {
   for (j = 0; j < col; j++) 
    {
     if (i == j)
     sum = sum + matrix[i][j];
    }
   }
 
   //Print out the Result
   cout<<"\nAddition of Diagonal Array Elements in the Matrix is: "<<sum;
getch();
}

Enter the number of Rows : 2

Enter the number of Columns : 2

Enter the Element a[0][0] : 1
Enter the Element a[0][1] : 2
Enter the Element a[1][0] : 3
Enter the Element a[1][1] : 4

Addition of Diagonal Array Elements in the Matrix is: 5