C Program to Perform Matrix Multiplication

This C program performs matrix multiplication. Matrix multiplication is a fundamental operation in linear algebra, where two matrices are multiplied to produce a third matrix.

Matrix multiplication is a fundamental operation in linear algebra and has various applications in fields such as computer graphics, physics simulations, and optimization algorithms. In the context of computer programming, matrix multiplication involves multiplying two matrices to obtain a resultant matrix.

Program Statement

Write a C program to perform matrix multiplication of two input matrices and display the resultant matrix. The program should define a function matrixMultiplication that takes two input matrices mat1 and mat2 as parameters and computes the resultant matrix res. The program should also include a function displayMatrix to display the contents of a matrix on the console.

C Program to Perform Matrix Multiplication

#include <stdio.h>

#define ROW_A 3
#define COL_A 2
#define ROW_B 2
#define COL_B 3

void multiplyMatrices(int matA[][COL_A], int matB[][COL_B], int result[][COL_B]) {
    int i, j, k;

    for (i = 0; i < ROW_A; i++) {
        for (j = 0; j < COL_B; j++) {
            result[i][j] = 0;
            for (k = 0; k < COL_A; k++) {
                result[i][j] += matA[i][k] * matB[k][j];
            }
        }
    }
}

void displayMatrix(int matrix[][COL_B], int row, int col) {
    int i, j;

    for (i = 0; i < row; i++) {
        for (j = 0; j < col; j++) {
            printf("%d\t", matrix[i][j]);
        }
        printf("\n");
    }
}

int main() {
    int matrixA[ROW_A][COL_A] = {{1, 2},
                                 {3, 4},
                                 {5, 6}};

    int matrixB[ROW_B][COL_B] = {{7, 8, 9},
                                 {10, 11, 12}};

    int resultMatrix[ROW_A][COL_B];

    multiplyMatrices(matrixA, matrixB, resultMatrix);

   printf("Matrix A:\n");
    displayMatrix(matrixA, ROW_A, COL_A);

    printf("Matrix B:\n");
    displayMatrix(matrixB, ROW_B, COL_B);

    printf("Resultant Matrix:\n");
    displayMatrix(resultMatrix, ROW_A, COL_B);

    return 0;
}

How it Works

Here’s a step-by-step explanation of how the provided C program works to perform matrix multiplication:

1. The program defines the dimensions of the matrices using constants ROWS and COLS. In this example, both matrices are 3×3, but you can adjust the dimensions as needed.
2. The matrixMultiplication function takes three parameters: mat1, mat2, and res. These parameters represent the two input matrices and the resultant matrix, respectively.
3. Inside the matrixMultiplication function, three nested loops are used to iterate over the rows and columns of the matrices. The outer loop iterates over the rows of mat1, the middle loop iterates over the columns of mat2, and the inner loop calculates the dot product of the corresponding row and column.
4. For each element in the resultant matrix res[i][j], the inner loop calculates its value by multiplying the corresponding elements from mat1 and mat2 and accumulating the results. The accumulation is performed by adding the product to the existing value of res[i][j].
5. The displayMatrix function is defined to display the contents of a matrix on the console. It takes a matrix mat as a parameter and uses nested loops to iterate over its rows and columns. The elements of the matrix are printed row by row using printf.
6. In the main function, two input matrices mat1 and mat2 are defined and initialized with appropriate values. The resultant matrix result is also defined.
7. The matrixMultiplication function is called with mat1, mat2, and result as arguments to compute the resultant matrix.
8. After the matrix multiplication is performed, the program displays the input matrices mat1 and mat2 using the displayMatrix function.
9. Finally, the program displays the resultant matrix result using the displayMatrix function.

By executing these steps, the program performs matrix multiplication and displays the input matrices as well as the resultant matrix on the console, allowing you to observe the outcome of the matrix multiplication operation.

Input/Output