Problem Description: Write a Java program that accepts a matrix of M × N order and then interchange diagonals of the matrix.
Steps:
1. We can only interchange diagonals for a square matrix.
2. Create a square matrix of size [M × M].
3. Check the matrix is a square matrix or not. If the matrix is square then follow step 3 else terminate the program.
4. Apply logic for interchange diagonal of the matrix some logic is given below.
Method 1: Swap element a[i][i] and a[i][n – i -1]
for (j = 0; j < m; j++) {
temp = a[j][j];
a[j][j] = a[j][n – 1 – j];
a[j][n – 1 – j] = temp;
}
Example:
// Java Program to Accept a Matrix of Order M x N & // Interchange the Diagonals import java.util.Scanner;
public class InterchangeDiagonals {
public static void main(String[] args)
{
// declare variable
int m, n, i, j, temp;
// create a object of scanner class
Scanner sc = new Scanner(System.in);
System.out.print( "Enter number of rows " );
// take number of rows
m = sc.nextInt();
System.out.print( "Enter number of columns " );
// take number of columns
n = sc.nextInt();
// declare a mxn order array
int a[][] = new int [m][n];
// if block it's execute when m is equals to n
if (m == n) {
System.out.println(
"Enter all the values of matrix " );
// take the matrix inputs
for (i = 0 ; i < m; i++) {
for (j = 0 ; j < n; j++) {
a[i][j] = sc.nextInt();
}
}
System.out.println( "original Matrix:" );
// print the original matrix
for (i = 0 ; i < m; i++) {
for (j = 0 ; j < n; j++) {
System.out.print(a[i][j] + " " );
}
System.out.println( "" );
}
// perform interchange
for (j = 0 ; j < m; j++) {
temp = a[j][j];
a[j][j] = a[j][n - 1 - j];
a[j][n - 1 - j] = temp;
}
System.out.println(
" after interchanging diagonals of matrix " );
// print interchanged matrix
for (i = 0 ; i < m; i++) {
for (j = 0 ; j < n; j++) {
System.out.print(a[i][j] + " " );
}
System.out.println( "" );
}
}
// else block it's only execute when m is not equals
// to n
else {
System.out.println( "Rows not equal to columns" );
}
}
} |
Output:
Enter number of rows 3
Enter number of columns 3
Enter all the values of matrix
1
2
3
4
5
6
7
8
9
Original Matrix:
1 2 3
4 5 6
7 8 9
After interchanging diagonals of matrix
3 2 1
4 5 6
9 8 7
Example 2:
// Java Program to Accept a Matrix of Order MxN & // Interchange the Diagonals import java.util.Scanner;
public class InterchangeDiagonals {
public static void main(String[] args)
{
// declare variable
int m, n, i, j, temp;
// create a object of scanner class
Scanner sc = new Scanner(System.in);
System.out.print( "Enter number of rows " );
// take number of rows
m = sc.nextInt();
System.out.print( "Enter number of columns " );
// take number of columns
n = sc.nextInt();
// declare a mxn order array
int a[][] = new int [m][n];
// if block it's execute when m is equals to n
if (m == n) {
System.out.println(
"Enter all the values of matrix " );
// take input matrix
for (i = 0 ; i < m; i++) {
for (j = 0 ; j < n; j++) {
a[i][j] = sc.nextInt();
}
}
System.out.println( "original Matrix:" );
// print original matrix
for (i = 0 ; i < m; i++) {
for (j = 0 ; j < n; j++) {
System.out.print(a[i][j] + " " );
}
System.out.println( "" );
}
// performing interchange
for (j = 0 ; j < m; j++) {
temp = a[j][j];
a[j][j] = a[j][n - 1 - j];
a[j][n - 1 - j] = temp;
}
System.out.println(
" after interchanging diagonals of matrix " );
// print interchanged matrix
for (i = 0 ; i < m; i++) {
for (j = 0 ; j < n; j++) {
System.out.print(a[i][j] + " " );
}
System.out.println( "" );
}
}
// else block it's only execute when m is not equals
// to n
else {
System.out.println( "Rows not equal to columns" );
}
}
} |
Output:
Enter number of rows 2
Enter number of columns 1
Enter all the values of matrix
1
2
Rows not equal to columns