Example: Matrix Multiplication Using Functions in C

// Matrix Multiplication Using Functions
#include <stdio.h>

// Function to get matrix elements from the user
void getMatrixElements(int matrix[][10], int rows, int cols, char name) {
    printf("Enter elements for Matrix %c (%dx%d):\n", name, rows, cols);
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            printf("Enter element [%d][%d]: ", i, j);
            scanf("%d", &matrix[i][j]);
        }
    }
}

// Function to multiply two matrices
void multiplyMatrices(int firstMatrix[][10], int secondMatrix[][10], int resultMatrix[][10], int r1, int c1, int r2, int c2) {
    // Initializing elements of result matrix to 0
    for (int i = 0; i < r1; ++i) {
        for (int j = 0; j < c2; ++j) {
            resultMatrix[i][j] = 0;
        }
    }

    // Multiplying firstMatrix and secondMatrix and storing it in resultMatrix
    for (int i = 0; i < r1; ++i) {
        for (int j = 0; j < c2; ++j) {
            for (int k = 0; k < c1; ++k) {
                resultMatrix[i][j] += firstMatrix[i][k] * secondMatrix[k][j];
            }
        }
    }
}

// Function to display a matrix
void displayMatrix(int matrix[][10], int rows, int cols, char name) {
    printf("\nMatrix %c:\n", name);
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            printf("%d\t", matrix[i][j]);
        }
        printf("\n");
    }
}

int main() {
    int firstMatrix[10][10], secondMatrix[10][10], resultMatrix[10][10];
    int r1, c1, r2, c2;

    // Step 1: Get dimensions for the first matrix
    printf("Enter rows and columns for first matrix: ");
    scanf("%d %d", &r1, &c1);

    // Step 2: Get dimensions for the second matrix
    printf("Enter rows and columns for second matrix: ");
    scanf("%d %d", &r2, &c2);

    // Step 3: Validate matrix dimensions for multiplication
    while (c1 != r2) {
        printf("Error! Column of first matrix not equal to row of second.\n");
        printf("Enter rows and columns for first matrix again: ");
        scanf("%d %d", &r1, &c1);
        printf("Enter rows and columns for second matrix again: ");
        scanf("%d %d", &r2, &c2);
    }

    // Step 4: Get elements for the first matrix using a function
    getMatrixElements(firstMatrix, r1, c1, 'A');

    // Step 5: Get elements for the second matrix using a function
    getMatrixElements(secondMatrix, r2, c2, 'B');

    // Step 6: Perform matrix multiplication using a function
    multiplyMatrices(firstMatrix, secondMatrix, resultMatrix, r1, c1, r2, c2);

    // Step 7: Display the matrices and the result using a function
    displayMatrix(firstMatrix, r1, c1, 'A');
    displayMatrix(secondMatrix, r2, c2, 'B');
    displayMatrix(resultMatrix, r1, c2, 'C'); // Result matrix dimensions are r1 x c2

    return 0;
}