Example for BGMAMMA

#include <iostream>
#include <string>
#include <iomanip>
using namespace std;

// main method at the end of file

int problem1(double a, double b, double c) {
    string validTriangleMessage = "The triangle is a valid right angle triangle.\n";
    string invalidTriangleMessage = "No triangle can be constructed from the given sides.\n";
    string invalidPythagoreanTripleMessage = "There exists no such a right angle triangle with the given sides.\n";
    string noNegativeSidesMessage = "Sides of a triangle must be positive\n";

    if (a < 0 || b < 0 || c < 0) {
        cout << noNegativeSidesMessage;

        return(1);
    }

    // is it really safe to compare doubles for equality in C++?
    // triangle inequality
    bool isValidTriangle = (a < c + b) && (b < a + c) && (c < a + b);
    // for the case where the sides of the triangle are given arbitrarily
    bool isValidPythagoreanTriple = (a * a + b * b == c * c) || (c * c + b * b == a * a) || (c * c + a * a == b * b);

    if (isValidTriangle)
    {
        if (isValidPythagoreanTriple) {
            cout << validTriangleMessage;
        }
        else {
            cout << invalidPythagoreanTripleMessage;
        }
    }
    else {
        cout << invalidTriangleMessage;
    }

    cout << endl;
}

void problem2(double a, double b, double c) {
    // variant 1 - conditional statements
    double max_if = 0;

    if (a >= b && a >= c)
    {
        max_if = a;
    }
    else if (b >= c && b >= a)
    {
        max_if = b;
    }
    else
    {
        max_if = c;
    }

    cout << "The maximum of the 3 numbers (calculated with IFs) is:  " << max_if << endl;
    //variant2 - using array and loops

    double numbers[3] = { a, b, c };
    double max_loop = -numeric_limits<double>::max();
    for (int i = 0; i < size(numbers); i++)
    {
        if (numbers[i] >= max_loop) {
            max_loop = numbers[i];
        }
    }

    cout << "The maximum of the 3 numbers (calculated with loop) is: " << max_loop << endl;
    cout << endl;
}

void problem3(int number) {
    for (int i = 1; i <= number; ++i)
    {
        if (i == 1)
        {
            cout << setw(3) << "X";
            for (int k = 1; k <= number; k++)
            {
                cout << setw(6) << k;
            }

            cout << endl;
            for (int i = 0; i <= 6 * number; i++)
            {
                cout << "-";
            }

            cout << "---" << endl;
        }

        cout << std::setw(3) << i;
        for (int j = 1; j <= number; ++j)
        {
            cout << setw(6) << i * j;
        }

        cout << endl;//<< endl;
    }
}

int main() {
    //cout << "Please enter a number to run the corresponding program (1, 2 or 3) or anything else to exit." << endl;
    int programNumber;
    while (true)
    {
        cout << "Please enter a number to run the corresponding program (1, 2 or 3) or anything else to exit." << endl;
        cin >> programNumber;
        double a, b, c;
        switch (programNumber)
        {
        case 1:
            cout << "Please enter three numbers to check if they can be sides of a right angle triangle" << endl;
            cin >> a >> b >> c;
            problem1(a, b, c);
            break;
        case 2:
            cout << "Please enter three numbers. The program will return the biggest one." << endl;
            cin >> a >> b >> c;
            problem2(a, b, c);
            break;
        case 3:
            cout << "Please enter an integer. The program will create the multiplication table up to this integer." << endl;
            int n;
            cin >> n;
            problem3(n);
            break;
        default:
            cout << "You have to choose 1, 2 or 3. Goodbye." << endl;
            return 0;
        }
    }
}