C# calculation returns 0

Question

I am new to C# and this code always returns 0.00 and I don't know what is the reason. Could anyone help? It is a console program and a possible input is

sofia
1500

the result should be 120.00

using System;

namespace TradeComissions
{
    class TradeComissions
    {
        static void Main(string[] args)
        {
            var town = Console.ReadLine().ToLower();
            var amount = double.Parse(Console.ReadLine());
            double result = 0.0;

            if(town == "sofia")
            {
                if (amount >= 0 && amount <= 500) 
                {                 
                    result = amount * (5 / 100);    
                }
                else if (amount >= 500 && amount <= 1000) 
                {         
                    result = amount * (7 / 100);    
                }
                else if (amount >= 1000 && amount <= 10000) 
                {       
                    result = amount * (8 / 100);    
                }
                else if (amount > 10000) 
                {                          
                    result = amount * (12 / 100);   
                }
            }

            Console.WriteLine("{0:f2}", result);
        }
    }
}

Yup, all your divisions are being done with integer arithmetic... — Jon Skeet, Jun 13 '17 at 11:22
`8 / 100 = 0` as they are marked as integers, use `8.0 / 100` or `8 / 100.0` to make sure it's a double calculation — Icepickle, Jun 13 '17 at 11:22
By the way, if you just removed parentheses, the result would be correct. — Sergey Kalinichenko, Jun 13 '17 at 11:23

ΦXocę 웃 Пepeúpa ツ · Accepted Answer · 2017-06-13T11:25:24.560

4

You are doing a mathematical division between 2 integers where denom is bigger that numerator e.g. 5 / 100, that operation result into an integer too (zero), do instead:

result = amount * (5.0 / 100);

edited Jun 13 '17 at 11:25

answered Jun 13 '17 at 11:23

ΦXocę 웃 Пepeúpa ツ

47,427
17
69
97

why was the duplicate marking not stopping you from answering? – Icepickle Jun 13 '17 at 11:25
hummm kind of weird, it was closed 3 minutes ago, my answer came 1 minute after closing.... – ΦXocę 웃 Пepeúpa ツ Jun 13 '17 at 11:26
Yeah, hence my question :) Seems it's a known [bug](https://meta.stackoverflow.com/questions/252711/this-answer-was-posted-after-the-question-was-closed-how-is-that-possible) :) – Icepickle Jun 13 '17 at 11:26
1

Well, it is more concerning that rep-farming is still successful on this site, even for extremly obvious dupes -.- – Tom Jun 13 '17 at 11:47

score 0 · Answer 2 · edited Aug 16 '18 at 10:04

This will work:

static void Main(string[] args)
{
    var town = Console.ReadLine().ToLower();
    var amount = double.Parse(Console.ReadLine());
    double result = 0.0;

    if (town == "sofia")
    {
        if (amount >= 0 && amount <= 500)
        {
            result = amount * (0.05);
        }
        else if (amount >= 500 && amount <= 1000)
        {
            result = amount * (0.07);
        }
        else if (amount >= 1000 && amount <= 10000)
        {
            result = amount * (0.08);
        }
        else if (amount > 10000)
        {
            result = amount * (0.12);
        }
    }
    double f = result;

    Console.WriteLine("{0:f2}", result);
    Console.ReadKey();
}

C# calculation returns 0

2 Answers2