Calling methods from cases (c #) error - argument: unable to transfer float to int

Question

We have assignment where we are supposed to code console application, which counts two values, perimeter and volume of triangle and regular hexagon. User should input values accordingly. We should use menu, where user selects which shape he wants to count. As menu i used switch case. I defined functions to count the volume and perimeter outside of main function. Now the problem i have is, that i dont know how to call the functions out of my cases. Hope i described it correctly.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp7
{
  class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("Daniel Nosek");
        Console.WriteLine("Výpočet obvodu a obsahu - trojúhelník, pravidelný šestiúhelník");
        Console.WriteLine("Zvolte si obrazec:");
        Console.WriteLine("1 - trojúhelník");
        Console.WriteLine("2 - pravidelný šestiúhelník");

        int VolbaObrazce = int.Parse(Console.ReadLine());
        double obvod = 0;
        double obsah = 0;
        switch (VolbaObrazce)
        {
            case 1:
                Console.WriteLine("Zadejte délku strany a:");
                float a = float.Parse(Console.ReadLine());
                Console.WriteLine("Zadejte délku strany b:");
                float b = float.Parse(Console.ReadLine());
                Console.WriteLine("Zadejte délku strany c:");
                float c = float.Parse(Console.ReadLine());

                obvod = ObvodTrojuhelniku(a, b, c);
                obsah = ObsahTrojuhelniku(a, b, c, s);
                break;

            case 2:
                Console.WriteLine("Zadejte délku strany d:");
                float d = float.Parse(Console.ReadLine());

                obvod = ObvodSestiuhelniku(d);
                obsah = ObsahSestiuhelniku(d);
                break;
        }


    }

    static int ObvodTrojuhelniku(int a, int b, int c) // vypocet obvodu pomoci souctu stran
    {
        return a + b + c;
    }

    static double ObsahTrojuhelniku(int a, int b, int c, int s) // obsah pomoci heronova vzorce
    {
        s = (a + b + c) / 2;
        return (double)Math.Sqrt(s * (s - a) * (s - b) * (s - c));
    }

    static int ObvodSestiuhelniku(int d) // obvod sestiuhelniku
    {
        return 6 * d;
    }
    static double ObsahSestiuhelniku(int d) // obsah sestiuhelniku
    {
        return ((3 * Math.Sqrt(3) * Math.Pow(d, 2))) / 2;
    }

}

}

Answer 1

Here, i fixed your parameter issues and i also took the freedom to switch up some of your Types:

static void Main(string[] args)
{
    Console.WriteLine("Daniel Nosek");
    Console.WriteLine("Výpočet obvodu a obsahu - trojúhelník, pravidelný šestiúhelník");
    Console.WriteLine("Zvolte si obrazec:");
    Console.WriteLine("1 - trojúhelník");
    Console.WriteLine("2 - pravidelný šestiúhelník");

    int VolbaObrazce = int.Parse(Console.ReadLine());
    double obvod = 0;
    double obsah = 0;

    bool recalculate = false;

    do
    {
        Console.Clear();

        switch (VolbaObrazce)
        {
            case 1:
                double a = ReadInVariable("Zadejte délku strany a:");
                double b = ReadInVariable("Zadejte délku strany b:");
                double c = ReadInVariable("Zadejte délku strany c:");

                obvod = ObvodTrojuhelniku(a, b, c);
                obsah = ObsahTrojuhelniku(a, b, c);
                break;

            case 2:
                double d = ReadInVariable("Zadejte délku strany d:");

                obvod = ObvodSestiuhelniku(d);
                obsah = ObsahSestiuhelniku(d);
                break;
            default:
                return;
        }

        // Output your results
        Console.WriteLine("obvod: " + Math.Round(obvod, 2, MidpointRounding.AwayFromZero)); // this will round to 2 digits after the .
        Console.WriteLine("obsah: " + Math.Round(obsah, 2, MidpointRounding.AwayFromZero));

        // check if the read in variable is equal to 1 and write that (true or false)
        // into the variable 'recalculate'
        recalculate = ReadInVariable("If you want to recalculate, enter 1:") == 1;
    }
    while(recalculate);
}

static double ReadInVariable(string text)
{
    Console.Write(text);
    return double.Parse(Console.ReadLine());
}

static double ObvodTrojuhelniku(double a, double b, double c) // vypocet obvodu pomoci souctu stran
{
    return a + b + c;
}

static double ObsahTrojuhelniku(double a, double b, double c) // obsah pomoci heronova vzorce
{
    double s = (a + b + c) / 2;
    return Math.Sqrt(s * (s - a) * (s - b) * (s - c));
}

static double ObvodSestiuhelniku(double d) // obvod sestiuhelniku
{
    return 6 * d;
}

static double ObsahSestiuhelniku(double d) // obsah sestiuhelniku
{
    return ((3 * Math.Sqrt(3) * Math.Pow(d, 2))) / 2;
}

I decided to switch the return type of the methods ObvodTrojuhelniku and ObvodSestiuhelniku from int to double, since you store them in a double anyways and it would just produce unnecessary casting.

I also changed your read-in variables from float to double since it makes everything a little easier and i don't see a point why you should be using float over double unless it's an requirement.

EDIT: I improved the code a little more by extracting the "reading in a variable"-functionality.

EDIT 2: Added Math.Round and the ability to recalculate values.

If you have any questions feel free to ask.