How Can I Prevent Rounding Decimals?

Question

I'm using c#, every time i insert 3 decimal places, the number gets rounded eg

1.538

rounds

to 1.54

I want the number to be as is eg 1.53 (to two decimal places only without any roundings).

How can i do it?

Answer 1

I believe you want to use Math.Truncate()

float number = 1.538
number = Math.Truncate(number * 100) / 100;

Truncate will lop off the end bit. However, bear in mind to be careful with negative numbers.

It depends on whether you always want to round towards 0, or just lop off the end, Math.Floor will always round down towards negative infinity. Here's a post on the difference between the two.

Answer 2

Found this link which gives a good code snippet to allow you to specify the number decimals places you want like Math.Round() allows.

Basically it's this:-

public static double Floor(this double d, int decimals) {
    return Math.Floor(d * Math.Pow(10, decimals)) / Math.Pow(10, decimals);
}