Matrix Multiplication in C

A simple, command-line C program to perform matrix multiplication. This project demonstrates the fundamental algorithm for multiplying two matrices, including the necessary condition checks.

Features

• Dynamic Sizing: Takes the number of rows and columns for two matrices from user input.
• Compatibility Check: Verifies that the matrices can be multiplied (i.e., the number of columns in the first matrix must equal the number of rows in the second).
• User-Friendly Input: Prompts the user to enter each element of the matrices.
• Result Display: Prints the resulting product matrix to the console in a clean, readable format.

Getting Started

To get a local copy up and running, follow these simple steps.

Prerequisites

You need a C compiler installed on your system. The most common is gcc.

• To check if you have gcc:

  gcc --version

Compilation

1. Clone the repo or save the matrix_multiplication.c file to your local machine.
2. Open your terminal or command prompt and navigate to the directory where you saved the file.
3. Compile the program using the following command:

   gcc matrix_multiplication.c -o matrix_multiplication

   This command compiles the C source file (matrix_multiplication.c) and creates an executable file named matrix_multiplication.

Execution

1. Run the compiled program from your terminal:

   ./matrix_multiplication

2. Follow the on-screen prompts to enter the dimensions and elements of your two matrices.

Example Usage

Here is an example of multiplying a 2x3 matrix by a 3x2 matrix.

$ ./matrix_multiplication

enter the rows and coloumns of first matrix
Rows:2
Columns:3
enter the 0 row and 0 column element: 1
enter the 0 row and 1 column element: 2
enter the 0 row and 2 column element: 3
enter the 1 row and 0 column element: 4
enter the 1 row and 1 column element: 5
enter the 1 row and 2 column element: 6

enter the rows and coloumns of second matrix: 
Rows:3
Column:2
enter the 0 row and 0 column element: 7
enter the 0 row and 1 column element: 8
enter the 1 row and 0 column element: 9
enter the 1 row and 1 column element: 10
enter the 2 row and 0 column element: 11
enter the 2 row and 1 column element: 12

58 64 
139 154
Use code with caution.
Markdown
In case of an error (incompatible matrices):
$ ./matrix_multiplication

enter the rows and coloumns of first matrix
Rows:2
Columns:2

...

enter the rows and coloumns of second matrix: 
Rows:3
Column:2

the matrices cannot be miltiplied
Use code with caution.
Bash
Code Explanation
The core logic of the program resides in three nested for loops, which execute after confirming that columns_of_A == rows_of_B.
// Condition check
if (col1 == row2)
{
    // Loop through each row of the first matrix
    for (i = 0; i < row1; i++)
    {
        // Loop through each column of the second matrix
        for (j = 0; j < col2; j++)
        {
            // Calculate the dot product for the element c[i][j]
            for (k = 0; k < col1; k++)
            {
                sum = sum + a[i][k] * b[k][j];
            }
            c[i][j] = sum;
            sum = 0; // Reset sum for the next element
        }
    }
}

Use code with caution.
C
Limitations and Future Improvements
Fixed-Size Result Matrix: The result matrix c is declared with a fixed size of int c[50][50]. This will cause a buffer overflow if the user inputs dimensions larger than 50.
Improvement: Use dynamic memory allocation (malloc) to create a result matrix of the exact required size.
No Input Validation: The program does not check if the user input is a valid number. Entering non-integer characters will cause undefined behavior.
Improvement: Add input validation loops to ensure the user enters valid integers for dimensions and elements.
Result Printing on Failure: The code to print the result matrix runs even if the multiplication fails. This will print uninitialized garbage data from memory.
Improvement: The final for loops for printing the result should be moved inside the if (col1 == row2) block.