Example: Calculate Diagonal from Width and Height in C++

// Calculate Diagonal from Width and Height
#include <iostream> // For input/output
#include <cmath>    // For sqrt and pow functions
#include <iomanip>  // For setting output precision

int main() {
    // Step 1: Declare variables for width, height, and diagonal
    double width, height, diagonal;

    // Step 2: Prompt user for width
    std::cout << "Enter the width of the rectangle: ";
    std::cin >> width;

    // Step 3: Prompt user for height
    std::cout << "Enter the height of the rectangle: ";
    std::cin >> height;

    // Step 4: Check for valid input (positive dimensions)
    if (width <= 0 || height <= 0) {
        std::cout << "Error: Width and height must be positive values." << std::endl;
        return 1; // Indicate an error
    }

    // Step 5: Calculate the diagonal using the Pythagorean theorem
    // diagonal = sqrt(width^2 + height^2)
    diagonal = std::sqrt(std::pow(width, 2) + std::pow(height, 2));

    // Step 6: Display the result
    std::cout << std::fixed << std::setprecision(2); // Format output to 2 decimal places
    std::cout << "The diagonal of the rectangle is: " << diagonal << std::endl;

    return 0; // Indicate successful execution
}