Converting number to number with two decimals

Question

Sorry if this question has already been asked I just can't find how to do it in my problem. I imported a file with a list of numbers from 1-20 into a listbox and then displayed the total amount of values and average into textboxes. I'm getting the right calculations it's just I have no clue how to convert them.

My code is:

int i = 0;
int result = 0;
while (i < lstbxDisplayInfo.Items.Count)
{
   result += Convert.ToInt32(lstbxDisplayInfo.Items[i++]);
}
//Displays average.
txtAverage.Text = Convert.ToString((double)result / i);
//Displays Amount.
txtAmount.Text = Convert.ToString((double) i);

my output is:

Average: 10.5
Total Amount: 20

I need the output to be:

Average: 10.50
Total Amount: 20.00

[Custom Numeric Format Strings](http://msdn.microsoft.com/library/0c899ak8.aspx) — Corak, Nov 27 '13 at 12:40

Soner Gönül · Answer 1 · 2013-11-27T12:51:28.333

6

You can use .ToString() method with #.00 format like;

(10.5).ToString("#.00");
(20).ToString("#.00");

Output will be;

10.50
20.00

Here a demonstration.

The "#" Custom Specifier

The "#" custom format specifier serves as a digit-placeholder symbol. If the value that is being formatted has a digit in the position where the "#" symbol appears in the format string, that digit is copied to the result string. Otherwise, nothing is stored in that position in the result string.

EDIT: Of course # doesn't represents zeros, that's why you should use #.00 instead of #.## format.

edited Nov 27 '13 at 12:51

answered Nov 27 '13 at 12:39

Soner Gönül

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1

This converts `20.0` to `20` and not `20.00`. – Thorkil Holm-Jacobsen Nov 27 '13 at 12:43
@tahatmat Yeah, I figure out now. Thanks. Updated. – Soner Gönül Nov 27 '13 at 12:44

score 0 · Accepted Answer · answered Nov 27 '13 at 12:43

0

If you need two decimal places i would use decimal instead. Two display them you can use d.ToString("N2"). Here is a more concise LINQ approach:

var allNums = lstbxDisplayInfo.Items.Cast<object>()
    .Select(o => decimal.Parse(o.ToString()));
decimal average = allNums.Average();
decimal total = allNums.Sum();
Console.WriteLine(average.ToString("N2"));
Console.WriteLine(total.ToString("N2"));

answered Nov 27 '13 at 12:43

Tim Schmelter

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This helps a lot! I just changed the Console.WriteLine to txtAverage.Text and txtAmount to display in their textboxes. – user3041721 Nov 27 '13 at 12:58
But i Didn't mean the sum as total, sorry. I meant total numbers inputted into the listbox, what would I change Sum() to? – user3041721 Nov 27 '13 at 12:59
@user3041721: `Count` :) – Tim Schmelter Nov 27 '13 at 13:00
ah thanks! I was trying to use length lol – user3041721 Nov 27 '13 at 13:05

Converting number to number with two decimals

2 Answers2