# std::linear_congruential_engine

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< cpp‎ | numeric‎ | random

Defined in header `<random>` |  |
template< class UIntType, UIntType a, UIntType c, UIntType m > class linear_congruential_engine; |  | (since C++11)

`linear_congruential_engine` is a random number engine based on Linear congruential generator (LCG). A LCG has a state that consists of a single integer.

The transition algorithm of the LCG function is x
i+1 ← (ax
i+c) mod m.

The following typedefs define the random number engine with two commonly used parameter sets:

Defined in header `<random>`
Type | Definition
`minstd_rand0` | std::linear_congruential_engine<std::uint_fast32_t, 16807, 0, 2147483647> Discovered in 1969 by Lewis, Goodman and Miller, adopted as "Minimal standard" in 1988 by Park and Miller
`minstd_rand` | std::linear_congruential_engine<std::uint_fast32_t, 48271, 0, 2147483647> Newer "Minimum standard", recommended by Park, Miller, and Stockmeyer in 1993

### Member types

Member type | Definition
`result_type` | The integral type generated by the engine. Results are undefined if this is not an unsigned integral type.

### Member functions

##### Construction and Seeding

(constructor) | constructs the engine (public member function)
seed | sets the current state of the engine (public member function)

##### Generation

operator() | advances the engine's state and returns the generated value (public member function)
discard | advances the engine's state by a specified amount (public member function)

##### Characteristics

min [static] | gets the smallest possible value in the output range (public static member function)
max [static] | gets the largest possible value in the output range (public static member function)

### Non-member functions

operator==operator!= | compares the internal states of two pseudo-random number engines (function template)
operator<<operator>> | performs stream input and output on pseudo-random number engine (function template)

### Member objects

constexpr UIntType multiplier [static] | the multiplier term (a). (public static member constant)
constexpr UIntType increment [static] | the increment term (c). (public static member constant)
constexpr UIntType modulus [static] | the modulus term (m). (public static member constant)
constexpr UIntType default_seed [static] | the default seed (1). (public static member constant)

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