Example: Calculate Missing Side from Diagonal and One Side in C++

// Calculate Missing Side from Diagonal and One Side
#include <iostream>
#include <cmath>
#include <iomanip>

int main() {
    // Step 1: Declare variables
    double diagonal, knownSide, missingSide;

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

    // Step 3: Prompt user for the length of one known side
    std::cout << "Enter the length of one known side: ";
    std::cin >> knownSide;

    // Step 4: Check for valid input
    if (diagonal <= 0 || knownSide <= 0) {
        std::cout << "Error: Diagonal and side lengths must be positive." << std::endl;
        return 1;
    }
    if (knownSide >= diagonal) {
        std::cout << "Error: A side length cannot be greater than or equal to the diagonal." << std::endl;
        return 1;
    }

    // Step 5: Calculate the missing side
    // missing_side = sqrt(diagonal^2 - known_side^2)
    missingSide = std::sqrt(std::pow(diagonal, 2) - std::pow(knownSide, 2));

    // Step 6: Display the result
    std::cout << std::fixed << std::setprecision(2);
    std::cout << "The length of the missing side is: " << missingSide << std::endl;

    return 0;
}