RosettaCodeData/Task/Random-numbers/Eiffel/random-numbers.e

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class
APPLICATION
inherit
ARGUMENTS
create
make
feature {NONE} -- Initialization
l_time: TIME
l_seed: INTEGER
math:DOUBLE_MATH
rnd:RANDOM
Size:INTEGER
once
Result:= 1000
end
make
-- Run application.
local
ergebnis:ARRAY[DOUBLE]
tavg: DOUBLE
x: INTEGER
tmp: DOUBLE
text : STRING
do
-- initialize random generator
create l_time.make_now
l_seed := l_time.hour
l_seed := l_seed * 60 + l_time.minute
l_seed := l_seed * 60 + l_time.second
l_seed := l_seed * 1000 + l_time.milli_second
create rnd.set_seed (l_seed)
-- initialize random number container and math
create ergebnis.make_filled (0.0, 1, size)
tavg := 0;
create math
from
x := 1
until
x > ergebnis.count
loop
tmp := randomNormal / 2 + 1
tavg := tavg + tmp
ergebnis.enter (tmp , x)
x := x + 1
end
tavg := tavg / ergebnis.count
text := "Average: "
text.append_double (tavg)
text.append ("%N")
print(text)
tmp := 0
from
x:= 1
until
x > ergebnis.count
loop
tmp := tmp + (ergebnis.item (x) - tavg)^2
x := x + 1
end
tmp := math.sqrt (tmp / ergebnis.count)
text := "Standard Deviation: "
text.append_double (tmp)
text.append ("%N")
print(text)
end
randomNormal:DOUBLE
local
first: DOUBLE
second: DOUBLE
do
rnd.forth
first := rnd.double_item
rnd.forth
second := rnd.double_item
Result := math.cosine (2 * math.pi * first) * math.sqrt (-2 * math.log (second))
end
end