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.

If the array elements are:

1 2 3

4 5 6

7 8 9

Output: Sum of main diagonal elements = 15

Happy coding ;)

**Example:**If the array elements are:

1 2 3

4 5 6

7 8 9

Output: Sum of main diagonal elements = 15

### Required knowledge:

Basic C programming, For loop, Array, Matrix#### Main diagonal of matrix

Main diagonal of a matrix**A**is a collection of elements**A**_{ij}Such that*i = j*.### Program:

/** * C program to find sum of main diagonal elements of a matrix */ #include <stdio.h> int main() { int A[3][3]; int row, col, sum = 0; /* * Reads elements in matrix from user */ printf("Enter elements in matrix of size 3x3: \n"); for(row=0; row<3; row++) { for(col=0; col<3; col++) { scanf("%d", &A[row][col]); } } /* * Finds the sum of main diagonal elements */ for(row=0; row<3; 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

1 2 3

4 5 6

7 8 9

Sum of main diagonal elements = 15

Happy coding ;)

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