# C program to find sum of main diagonal elements of a matrix

Write a C program to read elements in a matrix and find the sum of main diagonal (major diagonal) elements of matrix. Find sum of all elements of main diagonal of a matrix. Logic to find sum of main diagonal elements of a matrix in C programming.

Example

Input

```Input array elements:
1 2 3
4 5 6
7 8 9```

Output

`Sum of main diagonal elements = 15`

## Required knowledge

Basic C programming, For loop, Array

### Main diagonal of matrix

Main diagonal of a matrix A is a collection of elements Aij Such that i = j. ## Program to find sum of main diagonal elements of a matrix

``````/**
* C program to find sum of main diagonal elements of a matrix
*/

#include <stdio.h>

#define SIZE 3 // Matrix size

int main()
{
int A[SIZE][SIZE];
int row, col, sum = 0;

/* Input elements in matrix from user */
printf("Enter elements in matrix of size %dx%d: \n", SIZE, SIZE);
for(row=0; row<SIZE; row++)
{
for(col=0; col<SIZE; col++)
{
scanf("%d", &A[row][col]);
}
}

/* Find sum of main diagonal elements */
for(row=0; row<SIZE; row++)
{
sum = sum + A[row][row];
}

printf("\nSum of main diagonal elements = %d", sum);

return 0;
}``````

Output

```Enter elements in matrix of size 3x3:
1 2 3
4 5 6
7 8 9

Sum of main diagonal elements = 15```

Happy coding 😉 