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Point of view
All features
deferred class RANDOM_NUMBER_GENERATOR
Summary
Common abstract definition of a random number generator. The Liberty Eiffel library provides two implementations: MINIMAL_RANDOM_NUMBER_GENERATOR, and PRESS_RANDOM_NUMBER_GENERATOR. Most applications can safely rely on MINIMAL_RANDOM_NUMBER_GENERATOR. If you really need high quality randomizing, consider PRESS_RANDOM_NUMBER_GENERATOR.
Direct parents
Insert list: ANY
Known children
Inherit list: MINIMAL_RANDOM_NUMBER_GENERATOR
Overview
Features
{ANY}
  • make
    Create (or reset) the random number generator with an automatic randomised setting of the seed_value based on the CPU clock.
  • with_seed (seed_value: INTEGER_32)
    Create (or reset) the random number generator with an explicit seed_value.
  • next
    Prepare the next random number in sequence.
  • last_real: REAL_64
    The last computed number in range 0.0 to 1.0 excluded (see ensure).
  • last_integer (n: INTEGER_32): INTEGER_32
    The last computed number in range 1 to n(see ensure).
{}
make
deferred procedure
{ANY}
Create (or reset) the random number generator with an automatic randomised setting of the seed_value based on the CPU clock.
See also with_seed.
with_seed (seed_value: INTEGER_32)
deferred procedure
{ANY}
Create (or reset) the random number generator with an explicit seed_value.
By using an explicit seed_value, one can replay the very same random sequense more than once
See also make.
next
deferred procedure
{ANY}
Prepare the next random number in sequence.
Change internal memory of Current in order to prepare the next random number in sequence.
See also last_real, last_integer.
last_real: REAL_64
deferred function
{ANY}
The last computed number in range 0.0 to 1.0 excluded (see ensure).
Internal memory is not changed and two calls will give the same Result. Use next to get a new random last_real value.
See also last_integer.
ensure
  • Result > 0 and Result <= 1
last_integer (n: INTEGER_32): INTEGER_32
deferred function
{ANY}
The last computed number in range 1 to n(see ensure).
Internal memory is not changed and two calls will give the same Result. Use next to get a new random last_integer value.
See also last_real.
require
  • n >= 1
ensure
  • 1 <= Result and Result <= n
clock_based_random_seed: INTEGER_32
effective function
{}
Some positive random value to be used as a seed which may change as much as possible in a random way.
ensure
  • Result > 0