Question

I have a string which needs a decimal place inserted to give a precision of 2.

3000 => 30.00  300 =>  3.00   30 =>   .30 

Answer 1

Given a string input, convert to integer, divide by 100.0 and use String.Format() to make it display two decimal places.

String.Format('{0,0:N2}', Int32.Parse(input) / 100.0) 

Smarter and without converting back and forth – pad the string with zeros to at least two characters and then insert a point two characters from the right.

String paddedInput = input.PadLeft(2, '0')  padedInput.Insert(paddedInput.Length - 2, '.') 

Pad to a length of three to get a leading zero. Pad to precision + 1 in the extension metheod to get a leading zero.

And as an extension method, just for kicks.

public static class StringExtension {   public static String InsertDecimal(this String @this, Int32 precision)   {     String padded = @this.PadLeft(precision, '0');     return padded.Insert(padded.Length - precision, '.');   } }  // Usage '3000'.InsertDecimal(2); 

Note: PadLeft() is correct.

PadLeft()   '3' => '03' => '.03' PadRight()  '3' => '30' => '.30'