Finding the trace of a matrix

Here’s a Java program that calculates the trace of a square matrix:

    import java.util.Scanner;

    public class MatrixTrace {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter the number of rows/columns in the square matrix: ");

        int size = scanner.nextInt();

        int[][] matrix = new int[size][size];

        System.out.println("Enter the elements of the matrix:");

        // Reading matrix elements from the user

        for (int i = 0; i < size; i++) {

            for (int j = 0; j < size; j++) {

                matrix[i][j] = scanner.nextInt();

            }
        }

        // Calculating the trace of the matrix

        int trace = calculateTrace(matrix);

        System.out.println("The trace of the matrix is: " + trace);

    }

    public static int calculateTrace(int[][] matrix) {

        int trace = 0;

        int size = matrix.length;

        // Summing the diagonal elements

        for (int i = 0; i < size; i++) {

            trace += matrix[i][i];

        }

        return trace;

    }

}

In this program, we first prompt the user to enter the size of the square matrix. Then, we create a 2D array to store the matrix elements entered by the user.

Next, we calculate the trace of the matrix using the `calculateTrace()` method. The method iterates over the diagonal elements of the matrix and adds them to the `trace` variable.

Finally, we display the trace of the matrix to the user.