# Struct rand::StdRng [−] [src]

    pub struct StdRng {
        // some fields omitted
    }

The standard RNG. This is designed to be efficient on the current platform.

## Methods

### `impl StdRng`

#### `fn new() -> Result<StdRng>`

Create a randomly seeded instance of `StdRng`.

This is a very expensive operation as it has to read randomness from the operating system and use this in an expensive seeding operation. If one is only generating a small number of random numbers, or doesn't need the utmost speed for generating each number, `thread_rng` and/or `random` may be more appropriate.

Reading the randomness from the OS may fail, and any error is propagated via the `io::Result` return value.

## Trait Implementations

### `impl Rng for StdRng`

#### `fn next_u32(&mut self) -> u32`

#### `fn next_u64(&mut self) -> u64`

#### `fn next_f32(&mut self) -> f32`

#### `fn next_f64(&mut self) -> f64`

#### `fn fill_bytes(&mut self, dest: &mut [u8])`

#### `fn gen<T: Rand>(&mut self) -> T where Self: Sized`

#### `fn gen_iter<'a, T: Rand>(&'a mut self) -> Generator<'a, T, Self> where Self: Sized`

#### `fn gen_range<T: PartialOrd + SampleRange>(&mut self, low: T, high: T) -> T where Self: Sized`

#### `fn gen_weighted_bool(&mut self, n: u32) -> bool where Self: Sized`

#### `fn gen_ascii_chars<'a>(&'a mut self) -> AsciiGenerator<'a, Self> where Self: Sized`

#### `fn choose<'a, T>(&mut self, values: &'a [T]) -> Option<&'a T> where Self: Sized`

#### `fn shuffle<T>(&mut self, values: &mut [T]) where Self: Sized`

### `impl<'a> SeedableRng<&'a [usize]> for StdRng`

#### `fn reseed(&mut self, seed: &'a [usize])`

#### `fn from_seed(seed: &'a [usize]) -> StdRng`

### Derived Implementations

### `impl Clone for StdRng`

#### `fn clone(&self) -> StdRng`

#### `fn clone_from(&mut self, source: &Self)`1.0.0

### `impl Copy for StdRng`

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