Show the (decimal) value of a number of 1s appended with a 3, then squared: Difference between revisions
Show the (decimal) value of a number of 1s appended with a 3, then squared (view source)
Revision as of 21:46, 26 August 2021
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=={{header|Python}}==
===Procedural===
{{trans|FreeBASIC}}
<lang python>#!/usr/bin/python
Line 511 ⟶ 512:
m = make13(n)**2
print("{:d}\t\t{:d}".format(make13(n),m))</lang>
===Functional===
<lang python>'''Sequence of 1s appended with a 3, then squared'''
from itertools import islice
# seriesOfOnesEndingWithThree :: [Int]
def seriesOfOnesEndingWithThree():
'''An ordered and non-finite stream of integers
whose decimal digits end in 3, preceded only by a
series of (zero or more) ones.
(3, 13, 113, 1113 ...)
'''
def go(n):
return lambda x: n + 10 * x
return fmapGen(go(3))(
iterate(go(1))(0)
)
# showSquare :: (Int, Int, Int) -> String
def showSquare(ew, vw, n):
'''A string representation of the square of n,
both as an expression and as a value, with a
right-justfied expression column of width ew,
and a right-justified value column of width vw.
'''
return f'{str(n).rjust(ew)}^2 = {str(n ** 2).rjust(vw)}'
# ------------------------- TEST -------------------------
# main :: IO ()
def main():
'''Listing of the first 7 values of the series.'''
xs = take(7)(
seriesOfOnesEndingWithThree()
)
final = xs[-1]
w = len(str(final))
w1 = len(str(final ** 2))
print('\n'.join([
showSquare(w, w1, x) for x in xs
]))
# ----------------------- GENERIC ------------------------
# fmapGen <$> :: (a -> b) -> Gen [a] -> Gen [b]
def fmapGen(f):
'''A function f mapped over a
non finite stream of values.
'''
def go(g):
while True:
v = next(g, None)
if None is not v:
yield f(v)
else:
return
return go
# iterate :: (a -> a) -> a -> Gen [a]
def iterate(f):
'''An infinite list of repeated
applications of f to x.
'''
def go(x):
v = x
while True:
yield v
v = f(v)
return go
# take :: Int -> [a] -> [a]
def take(n):
'''The first n values of xs.
'''
return lambda xs: list(islice(xs, n))
# MAIN ---
if __name__ == '__main__':
main()</lang>
{{Out}}
<pre> 3^2 = 9
13^2 = 169
113^2 = 12769
1113^2 = 1238769
11113^2 = 123498769
111113^2 = 12346098769
1111113^2 = 1234572098769</pre>
=={{header|Quackery}}==
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