C# – Generate Random UInt

c++randomuint

I need to generate random numbers with range for byte, ushort, sbyte, short, int, and uint. I am able to generate for all those types using the Random method in C# (e.g. values.Add((int)(random.Next(int.MinValue + 3, int.MaxValue - 2)));) except for uint since Random.Next accepts up to int values only.

Is there an easy way to generate random uint?

Best Answer

The simplest approach would probably be to use two calls: one for 30 bits and one for the final two. An earlier version of this answer assumed that Random.Next() had an inclusive upper bound of int.MaxValue, but it turns out it's exclusive - so we can only get 30 uniform bits.

uint thirtyBits = (uint) random.Next(1 << 30);
uint twoBits = (uint) random.Next(1 << 2);
uint fullRange = (thirtyBits << 2) | twoBits;

(You could take it in two 16-bit values of course, as an alternative... or various options in-between.)

Alternatively, you could use NextBytes to fill a 4-byte array, then use BitConverter.ToUInt32.

Related Solutions

Random Number Generation in C# – Methods and Examples

The default seed is taken from the system clock.

I'm guessing that your GetRandomRectangle method was being called in quick succession and instantating a new instance of Random each time. When you do this, each instance of Random will take the same seed from the system clock, which is why your method created the same rectangle each time.

One solution is to create one instance of Random and pass that into your method:

Random rng = new Random();

Rectangle foo = GetRandomRectangle(rng);
Rectangle bar = GetRandomRectangle(rng);
Rectangle baz = GetRandomRectangle(rng);

// ...

public Rectangle GetRandomRectangle(Random rng)
{
    // create the rectangle using rng
}

C# – Generate a Random Integer

The Random class is used to create random numbers. (Pseudo-random that is of course.).

Example:

Random rnd = new Random();
int month  = rnd.Next(1, 13);  // creates a number between 1 and 12
int dice   = rnd.Next(1, 7);   // creates a number between 1 and 6
int card   = rnd.Next(52);     // creates a number between 0 and 51

If you are going to create more than one random number, you should keep the Random instance and reuse it. If you create new instances too close in time, they will produce the same series of random numbers as the random generator is seeded from the system clock.

Best Answer

Related Solutions

Random Number Generation in C# – Methods and Examples

C# – Generate a Random Integer

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