Arrays: Sum of two matrices

supriyo_biswas · updated April 11, 2020
#include <stdio.h>

int main() {
    // declare input and output arrays, and variables
    // for the number of rows and columns. there are
    // also two loop variables i and j.
    int a[10][10], b[10][10], sum[10][10], rows, cols, i, j;

    printf("Enter the number of rows:\n");
    scanf("%d", &rows);

    printf("Enter the number of columns:\n");
    scanf("%d", &cols);

    // check if the number of rows/columns requested
    // is too small or too large.
    if (rows < 1 || cols < 1 || rows > 10 || cols > 10) {
        printf("Invalid number of rows or columns\n");
        // exit the program
        return 0;
    }

    // ask for the numbers
    printf("Enter the numbers of the first matrix\n");

    for (i = 0; i < rows; i++) {
        for (j = 0; j < cols; j++) {
            // array index starts from 0, but row or
            // column number starts from 1.
            printf("Enter row %i, column %i:\n", i + 1, j + 1);
            scanf("%d", &a[i][j]);
        }
    }

    printf("Enter the numbers of the second matrix\n");

    for (i = 0; i < rows; i++) {
        for (j = 0; j < cols; j++) {
            // array index starts from 0, but row or
            // column number starts from 1.
            printf("Enter row %i, column %i:\n", i + 1, j + 1);
            scanf("%d", &b[i][j]);
        }
    }

    // calculate the sum of the matrix
    for (i = 0; i < rows; i++) {
        for (j = 0; j < cols; j++) {
            sum[i][j] = a[i][j] + b[i][j];
        }
    }

    printf("The first matrix is:\n");

    // print the first matrix
    for (i = 0; i < rows; i++) {
        for (j = 0; j < cols; j++) {
            printf("%d ", a[i][j]);
        }

        // to seperate the rows
        printf("\n");
    }

    printf("The second matrix is:\n");

    // print the second matrix
    for (i = 0; i < rows; i++) {
        for (j = 0; j < cols; j++) {
            printf("%d ", b[i][j]);
        }

        // to seperate the rows
        printf("\n");
    }

    printf("Sum of the matrix is:\n");

    // print the sum
    for (i = 0; i < rows; i++) {
        for (j = 0; j < cols; j++) {
            printf("%d ", sum[i][j]);
        }

        // to seperate the rows
        printf("\n");
    }

    return 0;
}
Output
(Run the program to view its output)

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