By | 29.11.2016

# Matrix Multiplication using Recursion

Write a C Program to implement Matrix Multiplication using Recursion. Here’s simple Program to implement Matrix Multiplication using Recursion in C Programming Language.

## Recursion : :

• Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.
• The C programming language supports recursion, i.e., a function to call itself. But while using recursion, programmers need to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.
• Recursive functions are very useful to solve many mathematical problems, such as calculating the factorial of a number, generating Fibonacci series, etc.

## Problem : :

The following C program, using recursion, performs Matrix multiplication of two matrices and displays the result. We use 2 D array to represent a matrix and resulting matrix is stored in a different matrix.

Here is the source code of the C Program to implement Matrix Multiplication using Recursion. The C Program is successfully compiled and run on a Linux system. The program output is also shown below.

### SOURCE CODE : :

```/*  C Program to implement Matrix Multiplication using Recursion  */

#include <stdio.h>

void multiply(int, int, int [][10], int, int, int [][10], int [][10]);
void display(int, int, int[][10]);

int main()
{
int a[10][10], b[10][10], c[10][10] = {0};
int m1, n1, m2, n2, i, j, k;

printf("Enter rows for Matrix A :: ");
scanf("%d", &m1);
printf("\nEnter cols for Matrix A :: ");
scanf("%d", &n1);
printf("\nEnter rows for Matrix B :: ");
scanf("%d", &m2);
printf("\nEnter cols for Matrix B :: ");
scanf("%d", &n2);

if (n1 != m2)
{
printf("\nMatrix multiplication not possible.\n");
}
else
{
printf("\nEnter elements in Matrix A :: \n");
for (i = 0; i < m1; i++)
for (j = 0; j < n1; j++)
{
printf("\nEnter A[%d][%d] element :: ",i,j);
scanf("%d", &a[i][j]);
}

printf("\nEnter elements in Matrix B :: \n");
for (i = 0; i < m1; i++)
for (j = 0; j < n1; j++)
{
printf("\nEnter B[%d][%d] element :: ",i,j);
scanf("%d", &a[i][j]);
}

multiply(m1, n1, a, m2, n2, b, c);
}
printf("\nAfter matrix multiplication of A and B, The result is A * B = C :: \n");

printf("\nElements in Matrix C are :: \n");

display(m1, n2, c);

return 0;
}

void multiply (int m1, int n1, int a[10][10], int m2, int n2, int b[10][10], int c[10][10])
{
static int i = 0, j = 0, k = 0;

if (i >= m1)
{
return;
}
else if (i < m1)
{
if (j < n2)
{
if (k < n1)
{
c[i][j] += a[i][k] * b[k][j];
k++;
multiply(m1, n1, a, m2, n2, b, c);
}
k = 0;
j++;
multiply(m1, n1, a, m2, n2, b, c);
}
j = 0;
i++;
multiply(m1, n1, a, m2, n2, b, c);
}
}

void display(int m1, int n2, int c[10][10])
{
int i, j;

for (i = 0; i < m1; i++)
{
for (j = 0; j < n2; j++)
{
printf("    %d   ", c[i][j]);
}
printf("\n");
}
}```

### Output : :

```/*  C Program to implement Matrix Multiplication using Recursion  */

Enter rows for Matrix A :: 2

Enter cols for Matrix A :: 2

Enter rows for Matrix B :: 2

Enter cols for Matrix B :: 2

Enter elements in Matrix A ::

Enter A[0][0] element :: 12

Enter A[0][1] element :: 56

Enter A[1][0] element :: 45

Enter A[1][1] element :: 78

Enter elements in Matrix B ::

Enter B[0][0] element :: 2

Enter B[0][1] element :: 6

Enter B[1][0] element :: 5

Enter B[1][1] element :: 8

After matrix multiplication of A and B, The result is A * B = C ::

Elements in Matrix C are ::
304       520
480       894

Process returned 0```

Above is the source code for C Program to implement Matrix Multiplication using Recursion which is successfully compiled and run on Windows System.The Output of the program is shown above .

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