Може ли някой да ми каже, как да го направя и да работи и с реални стойности! Мерси предварително!

using System;

namespace Homework5_Task4
{
class Program
{
static void Main()
{
/*
Write a program that shows the sign (+, - or 0) of the product of three real numbers,
without calculating it. Use a sequence of if operators
*/
// decimal a =decimal.TryParse((Console.ReadLine()), out "Invalid value");
string a = Console.ReadLine();
string b = Console.ReadLine();
string c = Console.ReadLine();
int negativecounter = 0;
int alength = 0;
int blength = 0;
int clength = 0;
for (int i = 0; i < a.Length; i++)
{
alength++;
}
for (int v = 0; v < b.Length; v++)
{
blength++;
}
for (int j = 0; j < c.Length; j++)
{
clength++;
}

if ((Convert.ToInt32(a) == 0) | (Convert.ToInt32(b) == 0) | (Convert.ToInt32(c) == 0))
{
Console.WriteLine("Answer is 0");
}
else
{
if (a[alength-alength] == '-')
{
negativecounter++;
}
if (b[blength-blength] == '-')
{
negativecounter++;
}
if (c[clength-clength] == '-')
{
negativecounter++;
}
}
if(negativecounter%2==0)
{
Console.WriteLine("+");
}
else
{
Console.WriteLine("-");
}
}
}
}