A Generic Clamp Function for C#

Introduction

This is my first C# generic function.

In computer terms, to clamp a value is to make sure that it lies between some maximum and minimum values. If it’s greater than the max value, then it’s replaced by the max, etc.

I first learned it in the context of computer graphics, for colors - it’s used, for instance, to make sure that your raytraced pixel isn't "blacker than black".

So:

    public static T Clamp<T>(T value, T max, T min)
         where T : System.IComparable<T> {     
        T result = value;
        if (value.CompareTo(max) > 0)
            result = max;
        if (value.CompareTo(min) < 0)
            result = min;
        return result;
    }

Usage

    int i = Clamp(12, 10, 0); -> i == 10
    double d = Clamp(4.5, 10.0, 0.0); -> d == 4.5

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I like more this one
Alberto Bencivenni

1:31 6 Feb '08

`public static void LimitRange<T>(T low, ref T value, T high) where T : IComparable { if (value.CompareTo(low) < 0) value = low; else if (value.CompareTo(high) > 0) value = high; }` This way don't need to assign a new variable. Alberto Bencivenni devDept
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Excellence milk for babes
JadeZhao

2:47 2 Feb '08

Thanks for you help .Hope some deepness articles self-given for yourself or I will think you a layabout only copy the SDK handbook. JadeZhao
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Great!
Jean-Paul Mikkers

10:34 1 Feb '08

I like it. Microsoft should add this to their framework.
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Usage examples
J4amieC

3:24 1 Feb '08

Am I missing something? Shouldn't: `int i = Clamp(12, 10, 0); -> i == 10 double d = Clamp(4.5, 10.0, 0.0); -> d == 4.5` be `int i = Clamp<int>(12, 10, 0); -> i == 10 double d = Clamp<double>(4.5, 10.0, 0.0); -> d == 4.5`
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Re: Usage examples
StockportJambo

5:36 1 Feb '08

You are missing something. The examples use type inference, which means the compiler works out the type of the generic by the parameters passed in. Since the author is passing in fixed values, this is easy enough for the compiler to do. Not that what you posted is wrong of course... it's just more verbose than it needs to be. Hope that helps.
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Re: Usage examples
J4amieC

1:10 2 Feb '08

thanks for clearing that up.
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Some comments.
Ennis Ray Lynch, Jr.

18:03 31 Jan '08

 
T Result = Value;
        if (Value.CompareTo(Max) > 0)
            Result = Max;
        if (Value.CompareTo(Min) < 0)
            Result = Min;
        return Result;

Should be

    T result = value;
    if (value.CompareTo(max) > 0)
        result = max;
    else if (value.CompareTo(min) < 0)
        result = min;
    return result;

Also from a best practices stand point your local variables as well as your parameters should be in camelCase and not PascalCase. It Is Much Easier To Read Applications When Casing Has Context, Plus It Is Easier To Type.

Need a C# Consultant? I'm available.

Happiness in intelligent people is the rarest thing I know. -- Ernest Hemingway

Re: Some comments.
mikemccabe

0:06 1 Feb '08

Fair enough. Several sources agree with you, so I've changed the convention. I'm still adapting from K+R
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Usage?
PCoffey

4:00 31 Jan '08

Can you give a couple of usage examples? it is interesting, but on the surface this looks like a generic method that was written for a very specific implementation.
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Re: Usage?
mikemccabe

12:58 31 Jan '08

You're right - especially given the generic syntax. I've posted two simple usage examples.
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Re: Usage?
Mladen Jankovic

13:55 31 Jan '08

mikemccabe wrote:
You're right - especially given the generic syntax.

Mostly, when you see programmers, they aren't doing anything. One of the attractive things about programmers is that you cannot tell whether or not they are working simply by looking at them. Very often they're sitting there seemingly drinking coffee and gossiping, or just staring into space. What the programmer is trying to do is get a handle on all the individual and unrelated ideas that are scampering around in his head. (Charles M Strauss)

Re: Usage?
PCoffey

4:32 1 Feb '08

cool. i get it now. Thanks for the examples.
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