Example: Display Lower Triangular Matrix in C++

// Display Lower Triangular Matrix
#include <iostream>
#include <vector> // Using vector for dynamic arrays, common in modern C++
#include <iomanip> // For std::setw to format output

int main() {
    // Step 1: Define the size of the square matrix
    const int SIZE = 3;

    // Step 2: Initialize a sample square matrix
    // This matrix will be used to demonstrate the lower triangular form
    std::vector<std::vector<int>> matrix = {
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9}
    };

    std::cout << "Original Matrix:" << std::endl;
    for (int i = 0; i < SIZE; ++i) {
        for (int j = 0; j < SIZE; ++j) {
            std::cout << std::setw(3) << matrix[i][j]; // Use setw for alignment
        }
        std::cout << std::endl;
    }
    std::cout << std::endl; // Add a blank line for readability

    std::cout << "Lower Triangular Matrix:" << std::endl;
    // Step 3: Iterate through the matrix to display the lower triangular form
    for (int i = 0; i < SIZE; ++i) { // Loop through rows
        for (int j = 0; j < SIZE; ++j) { // Loop through columns
            // Step 4: Check if the current element is part of the lower triangle
            // An element matrix[i][j] is in the lower triangle if j <= i
            if (j <= i) {
                std::cout << std::setw(3) << matrix[i][j]; // Print the actual element
            } else {
                std::cout << std::setw(3) << " "; // Print spaces for elements above the diagonal
            }
        }
        std::cout << std::endl; // Move to the next line after each row
    }

    return 0;
}