Java program for matrix multiplication and matrix transpose

In this article we will learn to implement a Java program for matrix multiplication and matrix transpose. A Java program is provided below to check the compatibility for multiplication, if compatible, multiplies two matrices and also finds its transpose.

import java.util.Scanner;
class Matrix
{
	void matrixMul(int m, int n, int p, int q)
	{
		int[][] a,b,c,t;
		a = new int[m][n];
		b = new int[p][q];
		c = new int[m][q];
		t = new int[q][m];
		Scanner s = new Scanner(System.in);
		System.out.println("Enter the elements of matrix A: ");
		for(int i = 0; i < m; i++)
		{
			for(int j = 0; j < n; j++)
			{
				a[i][j] = s.nextInt();
			}
		}
		System.out.println("Enter the elements of matrix B: ");
		for(int i = 0; i < p; i++)
		{
			for(int j = 0; j < q; j++)
			{
				b[i][j] = s.nextInt();
			}
		}
		for(int i = 0; i < m; i++)
		{
			for(int j = 0; j < q; j++)
			{
				for(int k = 0; k < n; k++)
				{
					c[i][j] += a[i][k]*b[k][j];
				}
			}
		}
		System.out.println("Elements of result matrix C are: ");
		for(int i = 0; i < m; i++)
		{
			for(int j = 0; j < q; j++)
			{
				System.out.print(c[i][j]+"\t");
			}
			System.out.print("\n");
		}
		for(int i = 0; i < q; i++)
		{
			for(int j = 0; j < m; j++)
			{
				t[i][j] = c[j][i];
			}
		}
		System.out.println("Elements of transpose matrix T are: ");
		for(int i = 0; i < q; i++)
		{
			for(int j = 0; j < m; j++)
			{
				System.out.print(t[i][j]+"\t");
			}
			System.out.print("\n");
		}
	}
}
class Driver
{
	public static void main(String[] args)
	{
		Scanner s = new Scanner(System.in);
		System.out.println("Enter no of rows in first matrix: ");
		int m = s.nextInt();
		System.out.println("Enter no of columns in first matrix: ");
		int n = s.nextInt();
		System.out.println("Enter no of rows in second matrix: ");
		int p = s.nextInt();
		System.out.println("Enter no of columns in second matrix: ");
		int q = s.nextInt();
		if(n == p)
		{
			Matrix obj = new Matrix();
			obj.matrixMul(m,n,p,q);
		}
		else
		{
			System.out.println("Matrix multiplication cannot be performed...");
		}
	}
}

Input and output for the above program is as follows:

Enter no of rows in first matrix:
3
Enter no of columns in first matrix:
3
Enter no of rows in second matrix:
3
Enter no of columns in second matrix:
3
Enter the elements of matrix A:
1 1 1
2 2 2
3 3 3
Enter the elements of matrix B:
1 2 3
1 2 3
1 1 1
Elements of result matrix C are:
3  5  7
6 10 14
9 15  21
Elements of transpose matrix T are:
3  6  9
5 10 15
7 14  21

Suryateja Pericherla

Suryateja Pericherla, at present is a Research Scholar (full-time Ph.D.) in the Dept. of Computer Science & Systems Engineering at Andhra University, Visakhapatnam. Previously worked as an Associate Professor in the Dept. of CSE at Vishnu Institute of Technology, India.

He has 11+ years of teaching experience and is an individual researcher whose research interests are Cloud Computing, Internet of Things, Computer Security, Network Security and Blockchain.

He is a member of professional societies like IEEE, ACM, CSI and ISCA. He published several research papers which are indexed by SCIE, WoS, Scopus, Springer and others.