CODEWITHSUNDEEP
c#random
hqt
hqt

Reputation: 30276

random double in four different interval

By my need in my application, I need to generate number from range 0 to 1, but with a little modify :

1. Range [0,1) : include 0 but not 1
2. Range (0, 1) : not include 0 nor 1
3. Range (0, 1] : same as 1. include 1 but not 0
4. Range [0,1]: include both 0 and 1

In C#, how can I random like this?

Upvotes: 1

Views: 161

Answers (2)

Guffa
Guffa

Reputation: 700192

Number one is easy, that's what's returned from the NextDouble method;

Random rnd = new Random();
double number = rnd.NextDouble();

To exclude the zero, pick a new number if you get a zero:

double number;
do {
  number = rnd.NextDouble();
} while(number == 0.0);

To include 1 but not 0, subtract the random number from 1:

double number = 1.0 - rnd.NextDouble();

To include both 0 and 1, you would use an approach similar to what King King suggests, with a sufficiently large number for your need:

double number = (double)rnd.Next(Int32.MaxValue) / (Int32.MaxValue - 1);

(Using ints you can get 31 bits of precision. If you need more than that you would need to use NextBytes to get 8 bytes that you can turn into a long.)

Upvotes: 3

King King
King King

Reputation: 63317

It depends on the precision you want, I suppose the precision is 0.001, try this code:

var rand = new Random();
//1
var next = (float) rand.Next(1000)/1000;
//2
var next = (float) rand.Next(1,1000)/1000;
//3
var next = (float) rand.Next(1,1001)/1000;
//4
var next = (float) rand.Next(1001)/1000;

Upvotes: 2

Related Questions