How to Find the "Clamp" Function in .Net

Where can I find the clamp function in .NET?

You could write an extension method:

public static T Clamp<T>(this T val, T min, T max) where T : IComparable<T>
{
    if (val.CompareTo(min) < 0) return min;
    else if(val.CompareTo(max) > 0) return max;
    else return val;
}

Extension methods go in static classes - since this is quite a low-level function, it should probably go in some core namespace in your project. You can then use the method in any code file that contains a using directive for the namespace e.g.

using Core.ExtensionMethods

int i = 4.Clamp(1, 3);

.NET Core 2.0

Starting with .NET Core 2.0 System.Math now has a Clamp method that can be used instead:

using System;

int i = Math.Clamp(4, 1, 3);

Fastest Way To Clamp an Integer

As easy as

var normalized = Math.Min(50, Math.Max(0, value));

As of performance:

  public static int Max(int val1, int val2) {
    return (val1>=val2)?val1:val2;
  }

That's how it's implemented in .NET, so it's unlikely you can implement it even better.

Does java have a clamp function?

Having looked at the generic clamp method offered up in another answer, it is worth noting that this has boxing/unboxing considerations for primitive types.

public static <T extends Comparable<T>> T clamp(T val, T min, T max) {...}

float clampedValue = clamp(value, 0f, 1f);

This will use the Float wrapper class, resulting in 3 box operations, one for each parameter, and 1 unbox operation for the returned type.

To avoid this, I would just stick to writing it long hand or use a non-generic function for the type you want:

public static float clamp(float val, float min, float max) {
    return Math.max(min, Math.min(max, val));
}

Then just overload with identical methods for every primitive type you require.

Where can I find the clamp function in .NET?

You could write an extension method:

public static T Clamp<T>(this T val, T min, T max) where T : IComparable<T>
{
    if (val.CompareTo(min) < 0) return min;
    else if(val.CompareTo(max) > 0) return max;
    else return val;
}

Extension methods go in static classes - since this is quite a low-level function, it should probably go in some core namespace in your project. You can then use the method in any code file that contains a using directive for the namespace e.g.

using Core.ExtensionMethods

int i = 4.Clamp(1, 3);

.NET Core 2.0

Starting with .NET Core 2.0 System.Math now has a Clamp method that can be used instead:

using System;

int i = Math.Clamp(4, 1, 3);

How to force a number to be in a range in C#?

I see Mark's answer and raise it by a this:

public static class InputExtensions
{
    public static int LimitToRange(
        this int value, int inclusiveMinimum, int inclusiveMaximum)
    {
        if (value < inclusiveMinimum) { return inclusiveMinimum; }
        if (value > inclusiveMaximum) { return inclusiveMaximum; }
        return value;
    }
}

Usage:

int userInput = ...;

int result = userInput.LimitToRange(1, 5)

See: Extension Methods

How can I make this simple method into a generic method?

You should use Compare method instead of < or > operators. And apply the correct generic constraints, for numeric types it should be IComparable, IComparable<T>, IConvertible, IEquatable<T>, IFormattable. However, you can leave only where T : struct, IComparable<T>, it should be enough for your purposes (but struct is important here, since you are comparing value types)

T coerce<T>(T val, T min, T max) where T : struct, IComparable, IComparable<T>, IConvertible, IEquatable<T>, IFormattable
{
    if (val.CompareTo(min) < 0)
        return min;
    if (val.CompareTo(max) > 0)
        return max;

    return val;
}

You can also specify the default min value like T min = default(T), but you can't do that for max value.

Following the comments, in case of using Nullable<T> for min and max values the code can be written like

T coerce<T>(T val, T? min = default, T? max = default) where T : struct, IComparable<T>
{
    var minValue = min.HasValue ? min.Value : default(T);
    var maxValue = max.HasValue ? max.Value : (T)Convert.ChangeType(10, typeof(T));

    if (val.CompareTo(minValue) < 0)
        return minValue;
    if (val.CompareTo(minValue) > 0)
        return maxValue;

    return val;
}

C# value overflow limiting

My new solution of this problem:

public static sbyte Clamp(this int val)
{
    return (sbyte)Math.Max(Math.Min(value, sbyte.MaxValue), sbyte.MinValue);
}

Call C++ functions from C#/.NET

You need to declare the class in C++/CLI as a ref class.

(Note that we're talking about C++/CLI, not C++. I assume you must have enabled the CLR in your C++ project or you wouldn't be able to get the new CFoo to work.)

Edit:

You don't need to convert all your old classes in to ref classes.

Suppose you have some old C++:

class FooUnmanaged
{
    int x;

    FooUnmanaged() : x(5) {}
};

Then you try to wrap it in a CLR class:

ref class FooManaged
{
    FooUnmanaged m;
};

As you've noticed, you get an error saying this isn't allowed. But try this:

ref class FooManaged
{
    FooUnmanaged *m;
};

That's perfectly OK. The compiler doesn't want to allocate an instance of an unmanaged object embedded inside an object on the managed heap, but it's quite happy to have a pointer, which it turns into System.IntPtr in the resulting IL.

This means that you have to make a decision about how to call delete. The most likely solution is:

ref class FooManaged
{
    FooUnmanaged *u;

public:
    FooManaged(FooUnmanaged *u_)
        : u(u_) { }

    ~FooManaged() { delete u; }
};

Just as it would be in any other C++ class. It's possible that C++/CLI will be able to do this translation for us automatically in some future version.

Note that the resulting IL is that the FooManaged class now implements IDisposable, and the destructor has been turned into a Dispose method. This allows .NET clients to properly deallocate it, e.g. in C#

using (var m = new FooManaged())
{

    // end of block: m will be disposed (and so FooUnmanaged will be deleted)
}

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