Example: Check if a matrix is an Identity Matrix in C

// Check if a matrix is an Identity Matrix
#include <stdio.h>
#include <stdbool.h> // For using boolean type

// Function to check if a matrix is an identity matrix
bool isIdentityMatrix(int matrix[10][10], int rows, int cols) {
    // Step 1: Check if the matrix is square
    if (rows != cols) {
        return false; // Not a square matrix, so cannot be an identity matrix
    }

    // Step 2: Iterate through all elements of the matrix
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            // Step 3: Check diagonal elements
            if (i == j) { // Current element is on the main diagonal
                if (matrix[i][j] != 1) {
                    return false; // Diagonal element is not 1
                }
            } else { // Current element is not on the main diagonal
                // Step 4: Check non-diagonal elements
                if (matrix[i][j] != 0) {
                    return false; // Non-diagonal element is not 0
                }
            }
        }
    }

    // Step 5: If all checks pass, it's an identity matrix
    return true;
}

int main() {
    int rows1 = 3, cols1 = 3;
    int matrix1[10][10] = {
        {1, 0, 0},
        {0, 1, 0},
        {0, 0, 1}
    };

    printf("Matrix 1:\n");
    for (int i = 0; i < rows1; i++) {
        for (int j = 0; j < cols1; j++) {
            printf("%d ", matrix1[i][j]);
        }
        printf("\n");
    }

    if (isIdentityMatrix(matrix1, rows1, cols1)) {
        printf("The matrix 1 is an Identity Matrix.\n\n");
    } else {
        printf("The matrix 1 is NOT an Identity Matrix.\n\n");
    }

    int rows2 = 3, cols2 = 3;
    int matrix2[10][10] = {
        {1, 0, 0},
        {0, 2, 0},
        {0, 0, 1}
    };

    printf("Matrix 2:\n");
    for (int i = 0; i < rows2; i++) {
        for (int j = 0; j < cols2; j++) {
            printf("%d ", matrix2[i][j]);
        }
        printf("\n");
    }

    if (isIdentityMatrix(matrix2, rows2, cols2)) {
        printf("The matrix 2 is an Identity Matrix.\n\n");
    } else {
        printf("The matrix 2 is NOT an Identity Matrix.\n\n");
    }

    int rows3 = 2, cols3 = 3; // Non-square matrix
    int matrix3[10][10] = {
        {1, 0, 0},
        {0, 1, 0}
    };

    printf("Matrix 3:\n");
    for (int i = 0; i < rows3; i++) {
        for (int j = 0; j < cols3; j++) {
            printf("%d ", matrix3[i][j]);
        }
        printf("\n");
    }

    if (isIdentityMatrix(matrix3, rows3, cols3)) {
        printf("The matrix 3 is an Identity Matrix.\n\n");
    } else {
        printf("The matrix 3 is NOT an Identity Matrix.\n\n");
    }

    return 0;
}