Java Program to determine whether a given matrix is an identity matrix

In the following examples of Java program to determine whether a given matrix is an identity matrix :

Program :

public class IdentityMatrix {
    public static void main(String[] args) {
        int[][] matrix = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}};
        boolean isIdentity = true;
        for (int i = 0; i < matrix.length; i++) {
            for (int j = 0; j < matrix[0].length; j++) {
                if (i == j && matrix[i][j] != 1) {
                    isIdentity = false;
                    break;
                }
                if (i != j && matrix[i][j] != 0) {
                    isIdentity = false;
                    break;
                }
            }
        }
        if (isIdentity) {
            System.out.println("The given matrix is an identity matrix.");
        } else {
            System.out.println("The given matrix is not an identity matrix.");
        }
    }
}

Output :

The given matrix is an identity matrix.

In this program, we have a matrix matrix represented as a two-dimensional array. We initialize a boolean variable isIdentity to true assuming that the matrix is an identity matrix.

We use two nested loops to iterate over the elements of the matrix. The outer loop iterates over the rows, and the inner loop iterates over the columns. For each element in the matrix, we check whether it is on the main diagonal (i.e., the element at row i and column j where i == j). If it is on the main diagonal, we check whether it is equal to 1. If it is not on the main diagonal, we check whether it is equal to 0. If either of these conditions is not satisfied, we set isIdentity to false and break out of both loops.

Finally, we print whether the matrix is an identity matrix or not.