# Idiom #15 Pick uniformly a random integer in [a..b]

Pick a random integer greater than or equals to a, inferior or equals to b. Precondition : a < b.

`import java.util.Random;`
```int pick(int a, int b){
return a + new Random().nextInt(b - a + 1);
}```
`#include <stdlib.h>`
```int pick(int a, int b)
{
int upper_bound = b - a + 1;
int max = RAND_MAX - RAND_MAX % upper_bound;
int r;

do {
r = rand();
} while (r >= max);
r = r % max;
return a + r;
}
```
`(+ a (rand-int (- b a)))`
`#include <random>`
```std::mt19937 gen;
std::uniform_int_distribution<size_t> uid (a, b);
uid (gen);
```
`using System;`
```Random r = new Random();
return r.next(a, b + 1);```
`import std.random;`
```auto x1 = uniform(a, b+1);
auto x2 = uniform!"[]"(a, b);```
`import 'dart:math';`
`int pick(int a, int b) => a + new Random().nextInt(b - a + 1);`
`a - 1 + :rand.uniform(b-a+1)`
`:crypto.rand_uniform(a, b)`
`crypto:rand_uniform(A, B)`
```real :: c
integer :: res

call random_number(c)
res = int((b-a+1)*c)
```
`import "math/rand"`
```func pick(a,b int) int {
return a + rand.Intn(b-a+1)
}```
`import System.Random`
```let pick (a, b) = randomRIO (a, b) :: IO Integer
in pick (1, 6) >>= print

```
```function pick(a, b) {
return a + Math.floor(Math.random() * (b - a + 1));
}```
`math.random(a, b)`
`a+arc4random_uniform(b+1)`
`rand(\$a, \$b)`
`Math`
```var
_a, _b, _r: Integer;
begin
_r := RandomRange(_a, _b);
end; ```
```my (\$min, \$max) = (5, 25);
my \$val = \$min + int(rand(\$max-\$min));
```
`import random`
`random.randint(a,b)`
`rand(a..b)`
```extern crate rand;
use rand::distributions::{IndependentSample, Range};```
```fn pick(a: i32, b: i32) -> i32 {
let between = Range::new(a, b);
between.ind_sample(&mut rng)
}
```
`use rand::distributions::Uniform;`
`Uniform::new_inclusive(a, b).sample(&mut rand::thread_rng())`
`import util.Random`
`a + Random.nextInt(b + 1)`

#### Idiom created by

programming-idioms.org