C Program to Multiply two Matrices by Passing Matrix to a Function

Introduction

Multiplying two matrices in a C program involves a detailed understanding of how matrices can be operated upon programmatically. This task is not only vital in academic courses but also has practical applications in the fields of engineering, computer graphics, and data analysis.

In this article, you will learn how to effectively multiply two matrices by passing them to a function in C. You will explore step-by-step examples that illustrate how to define matrices, pass them to functions, handle matrix multiplication, and return the result.

Defining the Matrix Structure

Create a Structure to Hold Matrix Data

1. Define a matrix structure which can hold the elements of the matrix and its dimensions.

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   typedef struct {
       int rows;
       int cols;
       int data[10][10]; // Adjust size as needed based on the maximum expected matrix size
   } Matrix;
   

   This code defines a Matrix type with rows and columns, and a two-dimensional array to hold the matrix data.

Function to Multiply Two Matrices

Developing the Matrix Multiplication Function

1. Write a function that accepts two matrices as parameters and returns the resulting matrix.

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   Matrix multiply_matrices(Matrix m1, Matrix m2) {
       Matrix result;
       result.rows = m1.rows;
       result.cols = m2.cols;
       // Initialize the result matrix with zero
       for(int i = 0; i < result.rows; i++) {
           for(int j = 0; j < result.cols; j++) {
               result.data[i][j] = 0;
           }
       }
       // Matrix multiplication logic
       for(int i = 0; i < m1.rows; i++) {
           for(int j = 0; j < m2.cols; j++) {
               for(int k = 0; k < m1.cols; k++) {
                   result.data[i][j] += m1.data[i][k] * m2.data[k][j];
               }
           }
       }
       return result;
   }
   

   This function first initializes the resulting matrix result based on the dimension of matrices m1 and m2. It then performs matrix multiplication by iterating through rows and columns, updating the result matrix accordingly.

Utilizing the Function in Code

Deployment in a Main Function

1. Create a main function to utilize the multiplication function and display the result.

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   #include <stdio.h>
   
   int main() {
       Matrix m1 = {2, 3, {{1, 2, 3}, {4, 5, 6}}};
       Matrix m2 = {3, 2, {{1, 2}, {3, 4}, {5, 6}}};
   
       Matrix result = multiply_matrices(m1, m2);
   
       // Displaying the result
       printf("Resultant Matrix:\n");
       for(int i = 0; i < result.rows; i++) {
           for(int j = 0; j < result.cols; j++) {
               printf("%d ", result.data[i][j]);
           }
           printf("\n");
       }
   
       return 0;
   }
   

   In the main function, two matrices, m1 and m2, are defined and initialized. The multiply_matrices() function is called with m1 and m2 as arguments, and the result is stored in result. Finally, the resultant matrix is printed to the console.

Conclusion

Multiplying two matrices by passing them to a function in C helps modularize your code and enhances clarity, making it easier to manage and debug. By following the discussed steps and leveraging structures for matrix data, you can handle matrix operations efficiently in your C programs. Whether for academic projects or practical applications, mastering these techniques serves as a strong foundation in programming fundamentals.