C# Percentage Calculation Explanation

Percentage calculation

(current / maximum) * 100. In your case, (2 / 10) * 100.

c# Percentage calculator

Try this

sum = (x * 3.4528) * 1.21;

C# percentage calculation suddenly goes negative

Lasse V. Karlsen gave the correct explanation in the comment.

To fix it, change:

var progress = (int) Math.Round((double) (100 * totalBytesCopied) / sourceLength);

into:

var progress = (int) Math.Round(((double)100) * totalBytesCopied / sourceLength);

or simply:

var progress = (int) Math.Round(100.0 * totalBytesCopied / sourceLength);

As he says, this will force everything to be done as floating point. The integers will automatically (implicitly) be converted to double in that case. I removed a redundant parenthesis (but you can also just keep it).

Calculate percentage if percentage sign is in the text

You can use this code,

private void txtdiscount_TextChanged(object sender, EventArgs e)
{
   if (txtdiscount.Text.Length > 0 && lbltotal.Text != "")
   {
      decimal net = 0, total = 0, discount = 0;
      total = Convert.ToDecimal(lbltotal.Text);
      if (txtdiscount.Text.IndexOf('%') != -1)
      {
        discount = total *  Convert.ToDecimal(txtdiscount.Text.Split('%')[0])/100;
      }
      else
      {
        discount = Convert.ToDecimal(txtdiscount.Text);
      }
      net =total- discount;
      lblnetamount.Text = net.ToString();

    }
 }

Calculating the percentage difference between two values

What to do in that situation is subjective, and likely depends on your business needs.

I would prefer Not Available if there is no other choice.

100% may make sense.

Maybe use 1 instead of zero may also make sense resulting in 2560% in your example.

What's the best way to create a percentage value from two integers in C#?

How about just mappedItems * 100.0 / totalItems and casting this to the appropriate type?

Percentage Based Probability

This is very easy to check for yourself:

Random rand = new Random(); 
int yes = 0;
const int iterations = 10000000;
for (int i = 0; i < iterations; i++)
{
   if (rand.Next(1, 101) <= 25)
   {
       yes++;
   }
}
Console.WriteLine((float)yes/iterations);

the result:

0.2497914

The conslusion: Yes, yes it is.

Edit: Just for fun, the LINQy version:

Random rand = new Random(); 
const int iterations = 10000000;
int sum = Enumerable.Range(1, iterations)
                    .Count(i => rand.Next(1, 101) <= 25);
Console.WriteLine(sum / (float)iterations);