Let’s learn java program to find transpose of a matrix.
Java program to find transpose of a matrix
Java program to display transpose matrix is one of the common interview question in java programming.
To print the transpose of a given matrix in java user enters number of rows and columns using nextInt() method of Scanner class.
Also read – java program for matrix multiplication
These user entered rows and columns are stored in interger variables ‘row’ and ‘col’. In the next step user enters matrix elements.
Transpose of a matrix in java can be performed by converting columns of matrix to row and rows of matrix to columns.
For example:
3x3 matrix a11 a12 a13 a21 a22 a23 a31 a32 a33 transposed 3x3 matrix a11 a21 a31 a12 a22 a32 a13 a23 a33
Let’s see java program to display transpose a matrix or transpose of a matrix in java using scanner,
import java.util.Scanner; public class MatrixTransposeInJava { public static void main(String[] args) { int a, b; System.out.println("Please enter rows and columns : "); // transpose of a matrix in java using scanner Scanner sc = new Scanner(System.in); int row = sc.nextInt(); int col = sc.nextInt(); int[][] arrNum = new int[row][col]; System.out.println("Please enter matrix elements : "); for(a = 0; a < row; a++) { for(b = 0; b < col; b++) { arrNum[a][b] = sc.nextInt(); } } System.out.println("Before transpose : "); for(a = 0; a < row; a++) { for(b = 0; b < col; b++) { System.out.print(arrNum[a][b] + " "); } System.out.println(" "); } System.out.println("After transpose : "); for(a = 0; a < col; a++) { for(b = 0; b < row; b++) { System.out.print(arrNum[b][a] + " "); } System.out.println(" "); } sc.close(); } }
Output:
Print 3×3 matrix
Let’s learn java program to print 3×3 matrix. Here’s 3×3 matrix in java example,
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class MatrixTransposeDemo
{
public static void main(String[] args) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int[][] inputNumber = new int[3][3];
int a, b;
String strMatrix;
System.out.println("Please enter elements to print 3x3 matrix: ");
for(a = 0; a <= 2; a++)
{
for(b = 0; b <= 2; b++)
{
strMatrix = br.readLine();
inputNumber[a][b]=Integer.parseInt(strMatrix);
}
}
System.out.println("Elements in 3x3 matrix are: ");
System.out.println("");
for(a = 0; a <= 2; a++)
{
for(b = 0; b <= 2; b++)
{
System.out.print(inputNumber[a][b] + "\t");
}
System.out.println();
}
}
}
Output:
Please enter elements to print 3×3 matrix:
2
4
6
8
1
3
5
7
9
Elements in 3×3 matrix are:
2 4 6
8 1 3
5 7 9
java program to find trace of a matrix
Trace of a matrix is nothing but sum of diagonal elements. For example consider square matrix m x m,
1 2 3 4 5 6 7 8 9
Trace of a matrix is: 1 + 5 + 9 = 15
Here we are going to learn java program to find trace of a matrix,
import java.util.Scanner;
public class TraceMatrixDemo
{
public static void main(String[] args)
{
int[][] arrInput = new int[10][10];
int a, b;
double total = 0;
System.out.println("Please enter total rows and columns: ");
Scanner sc = new Scanner(System.in);
int row = sc.nextInt();
int column = sc.nextInt();
System.out.println("Please enter matrix: ");
for(a = 0; a < row; a++)
{
for(b = 0; b < column; b++)
{
arrInput[a][b] = sc.nextInt();
System.out.print(" ");
}
}
System.out.println("Entered matrix is: ");
for(a = 0; a < row; a++)
{
for(b = 0; b < column; b++)
{
System.out.print(arrInput[a][b] + " ");
}
System.out.println(" ");
}
System.out.println("Trace of a matrix: ");
for(a = 0; a < row; a++)
{
for(b = 0; b < column; b++)
{
if(a == b)
{
total = total + (arrInput[a][b]);
}
}
}
System.out.println(total);
sc.close();
}
}
Output:
Please enter total rows and columns:
3
3
Please enter matrix:
2
4
6
8
1
3
5
7
9
Entered matrix is:
2 4 6
8 1 3
5 7 9
Trace of a matrix:
12.0
Using bufferedreader
Now let’s learn transpose of a matrix in java using bufferedreader. Here’s java program to transpose a matrix,
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class TransposeMatrixDemo
{
public static void main(String[] args) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Please enter number of rows: ");
int row = Integer.parseInt(br.readLine());
System.out.print("Please enter number of columns: ");
int col = Integer.parseInt(br.readLine());
int[][] arrMatrix = new int[row][col];
int[][] arrTranspose = new int[row][col];
System.out.println("Please enter elements of matrix: ");
for(int a = 0; a < row; a++)
{
for(int b = 0; b < col; b++)
{
arrMatrix[a][b] = Integer.parseInt(br.readLine());
}
}
System.out.println("Given Matrix\n");
for(int a = 0; a < row; a++)
{
for(int b = 0; b < col; b++)
{
System.out.print(arrMatrix[a][b] + " ");
}
System.out.print("\n");
}
for(int a = 0; a < row; a++)
{
for(int b = 0; b < col; b++)
{
arrTranspose[b][a] = arrMatrix[a][b];
}
}
System.out.println("Transpose matrix in java \n");
for(int a = 0; a < col; a++)
{
for(int b = 0; b < row; b++)
{
System.out.print(arrTranspose[a][b] + " ");
}
System.out.print("\n");
}
}
}
Output:
Please enter number of rows: 3
Please enter number of columns: 3
Please enter elements of matrix:
1
2
3
4
5
6
7
8
9
Given Matrix
1 2 3
4 5 6
7 8 9
Transpose matrix in java
1 4 7
2 5 8
3 6 9
transpose of matrix in java using function
Here’s the program for transpose of matrix in java using function,
public class TransposeUsingFunction
{
static final int num = 4;
public static void main(String[] args)
{
int[][] matrix1 = { {5, 5, 5, 5},
{6, 6, 6, 6},
{7, 7, 7, 7},
{8, 8, 8, 8}};
int[][] matrix2 = new int[num][num];
functionTranspose(matrix1, matrix2);
System.out.print("transpose of matrix using function: \n");
for(int a = 0; a < num; a++)
{
for(int b = 0; b < num; b++)
System.out.print(matrix2[a][b] + " ");
System.out.print("\n");
}
}
static void functionTranspose(int mat1[][], int mat2[][])
{
int a, b;
for(a = 0; a < num; a++)
for(b = 0; b < num; b++)
mat2[a][b] = mat1[b][a];
}
}
Output:
transpose of matrix using function:
5 6 7 8
5 6 7 8
5 6 7 8
5 6 7 8
Also read – multiplication of a matrix in java
transpose of a matrix in java without using second matrix
Let’s learn java program for transpose of a matrix in java without using second matrix,
import java.util.Scanner;
public class WithoutSecondMatrix
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
int a, b, row, column, temp;
System.out.println("Please enter number of rows: ");
row = sc.nextInt();
System.out.println("Please enter the number of columns: ");
column = sc.nextInt();
int[][] matrix = new int[row][column];
System.out.println("Please enter elements of matrix: ") ;
for(a = 0; a < row; a++)
{
for(b = 0; b < column; b++)
{
matrix[a][b] = sc.nextInt();
}
}
System.out.println("Elements of the matrix: ") ;
for(a = 0; a < row; a++)
{
for(b = 0; b < column; b++)
{
System.out.print(matrix[a][b] + "\t");
}
System.out.println("");
}
// transpose of a matrix
for(a = 0; a < row; a++)
{
for(b = 0; b < a; b++)
{
temp = matrix[a][b];
matrix[a][b] = matrix[b][a];
matrix[b][a] = temp;
}
}
System.out.println("transpose of a matrix without using second matrix: ") ;
for(a = 0; a < row; a++)
{
for(b = 0; b < column; b++)
{
System.out.print(matrix[a][b] + "\t");
}
System.out.println("");
}
sc.close();
}
}
Output:
Please enter number of rows: 3
Please enter the number of columns: 3
Please enter elements of matrix:
1 3 5
7 9 2
4 6 8
Elements of the matrix:
1 3 5
7 9 2
4 6 8
transpose of a matrix without using second matrix:
1 7 4
3 9 6
5 2 8