Example: Print Lower Triangular Matrix in C++

// Print Lower Triangular Matrix
#include <iostream>
#include <vector> // Using vector for dynamic array, but fixed-size array works too
#include <iomanip> // For std::setw to format output

int main() {
    // Step 1: Define the matrix dimensions
    int rows = 3;
    int cols = 3;

    // Step 2: Initialize the matrix (you can take user input here)
    std::vector<std::vector<int>> matrix = {
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9}
    };

    // Step 3: Print the original matrix (optional, for comparison)
    std::cout << "Original Matrix:\n";
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            std::cout << std::setw(3) << matrix[i][j];
        }
        std::cout << std::endl;
    }
    std::cout << std::endl;

    // Step 4: Print the lower triangular matrix
    std::cout << "Lower Triangular Matrix:\n";
    for (int i = 0; i < rows; ++i) {       // Iterate through rows
        for (int j = 0; j < cols; ++j) {   // Iterate through columns
            if (i >= j) {                  // Check if element is on or below the main diagonal
                std::cout << std::setw(3) << matrix[i][j];
            } else {                       // Element is above the main diagonal
                std::cout << std::setw(3) << " "; // Print spaces for alignment
            }
        }
        std::cout << std::endl;           // Move to the next line after each row
    }

    return 0;
}