In java, we have a 4 × 4 matrix, the task is to interchange the elements of the first and last rows and then return the resultant matrix.

Illustration:

Input 1:  1  1  5  0
          2  3  7  2
          8  9  1  3
          6  7  8  2
Output 1: 6  7  8  2
          2  3  7  2 
          8  9  1  3
          1  1  5  0

Input 2:  7   8   9  10
         11  13  14   1
         15   7  12  22
         11  21  30   1

Output 2: 11  21  30   1
         11  13  14   1
         15  7   12  22
         7   8   9   10

Approach:

To get the necessary yield, we need to trade the components of the first and the last column of the expressed lattice.

Example

// Java Program to Interchange Elements of First
// and Last Row in a Matrix

// Importing input output classes
import java.io.*;

// Main Class
public class GFG {

	// Method 1
	// To swap First and Last Row
	static void swap_First_last(int mat[][])
	{
		int rws = mat.length;

		// Interchanging of elements between the
		// first and last rows
		for (int j = 0; j < mat[0].length; j++) {

			// Using temporary variable so in order
			// not to loose the values of the matrix
			// Simply, swapping the values stored
			int temp = mat[0][j];
			mat[0][j] = mat[rws - 1][j];
			mat[rws - 1][j] = temp;
		}
	}

	// Method 2
	// Main driver method
	public static void main(String args[])
		throws IOException
	{
		// Input integer matrix
		int mat[][] = { { 2, 3, 4, 5 },
						{ 8, 9, 6, 15 },
						{ 13, 22, 11, 18 },
						{ 19, 1, 2, 0 } };

		// Display message only
		System.out.println("Input matrix is as follows : ");

		// Printing the Input matrix
		for (int j = 0; j < mat.length; j++) {
			for (int k = 0; k < mat[0].length; k++)

				// Print the elements of the input matrix
				System.out.print(mat[j][k] + " ");

			// New line as row ended
			System.out.println();
		}

		System.out.println(
			"Swapped matrix is as follows : ");

		// Calling the (method1) to swap rows in a matrix
		swap_First_last(mat);

		// Printing the Swapped matrix
		for (int j = 0; j < mat.length; j++) {
			for (int k = 0; k < mat[0].length; k++)

				// Print the elements of the swapped matrix
				System.out.print(mat[j][k] + " ");

			// New line as row ended
			System.out.println();
		}
	}
}

Output:

Input matrix is as follows : 
2 3 4 5 
8 9 6 15 
13 22 11 18 
19 1 2 0 
Swapped matrix is as follows : 
19 1 2 0 
8 9 6 15 
13 22 11 18 
2 3 4 5