C program to find the sum of all the elements of a matrix

In this article, you will learn and get code for finding the sum of all elements of a given matrix.

The question is: Write a C program that takes nine elements of a 3*3 matrix as input from the user (at run-time) and calculates the sum of all the matrix elements. The answer to this question is:

#include<stdio.h>
#include<conio.h>
int main()
{
    int mat[3][3], i, j, sum;
    sum = 0;
    printf("Enter all 9 elements of 3*3 Matrix:-\n");
    for(i=0; i<3; i++)
    {
        for(j=0; j<3; j++)
        {
            scanf("%d", &mat[i][j]);
            sum = sum + mat[i][j];
        }
    }
    printf("\nSum of all elements = %d", sum);
    getch();
    return 0;
}

The program was written in the Code::Blocks IDE; therefore, after a successful build and run, you will get the output as shown in the sample given here:

Enter all 9 elements and press the enter key. Here is the second screenshot of the sample run:

Program Explained

1. Take all 9 elements as input and initialize the matrix one by one.
2. The 3*3 matrix means it has 3 rows and 3 columns.
3. We have to use two for loops; the outer one is for rows, and the inner one is for columns.
4. In this manner
   • The first element is set to mat[0][0].
   • The second element is set to mat[0][1].
   • The third element is set to mat[0][2].
   • Similarly, the fourth, fifth, sixth, seventh, eighth, and ninth elements are initialized to mat[1][0], mat[1][1], mat[1][2], mat[2][0], mat[2][1], and mat[2][2].
5. At the time of scanning every element, the summation statement is applied.
6. Finally, print out the value of the sum variable. Never forget to set the sum variable to 0 before attempting to compute the sum of all matrix elements.

C Quiz