COP 4930 Python Programming Assignment 03 Read about the algorithm for the Sieve

Question

COP 4930 Python Programming

Assignment 03

Read about the algorithm for the Sieve of Eratosthenes at

http://wiki.answers.com/Q/What_is_the_sieve_of_eratosthenes&altQ=Sieve_of_Eratosthenes_1_to_100

See also

   http://math.ucsd.edu/~wgarner/math187/unicity.pdf

for a list of the prime numbers between 2 and 100.

Please write a program, save it in YourFAUID_lab03.py, that asks for
an upper range of numbers to search for prime numbers.
Start at 2 and go up to the number the user asked you to use.

Your program should make sure that the upper bound when searching for the
prime numbers is >= 2 and <= 300; otherwise your program should display
a message that upper bound is out of range and terminate the execution.

Write a function eratos that takes an int indicating the upper range of
the numbers and returns a list of ints containing the prime numbers
between 2 and n:

def eratos( n ) :

The algorithm indicates that the first number, 2, is a prime and every
multiple of if cannot be a prime, so "cross them out: 4, 6, 8, etc."
When the algorithm indicates one should "cross out" a number, that is another
way to say "remove that number from the list."
See the function remove( ) on 5.5.7, p54, textbook.

Write a second function,

   def print_primes( primes ) :

where primes is the list of ints that erators( ) generated.
This function should display 10 numbers per line and use 5 positions
for each number; if the user asked for an upper bound of 100,
your program should display

2 3 5 7 11 13 17 19 23 29
31 37 41 43 47 53 59 61 67 71
73 79 83 89 97

Penalties:
o no credit if your .py file does not run
o no credit if you do NOT use a Python list
o no credit if your .py file does not produce the correct results
as listed above
o no credit if you do not create two functions as described
o no credit for late assignments

Please upload to the BlackBoard a .py file named

YourFAUID_lab03.py

Explanation / Answer

# - - - - - - - - - - - - - Functions Defined Below - - - - - - - - - - - # def eratos(upper_limit): number_list = [] for number in range(2, upper_limit + 1): number_list.append(number) for i in number_list: for j in number_list: if j % i == 0 and i != j: number_list.remove(j) return number_list def print_primes(prime_list): print_count = 0 for prime_number in prime_list: print("%5d" % prime_number, end=" ") print_count += 1 if print_count >= 10: print_count = 0 print() def main(): print("Please enter a range to generate prime numbers...") print("Allowed ranges are 2 - 300") input_range = int(input("Range: ")) if input_range < 2 or input_range > 300: print("Invalid Range...") exit() else: print_primes(eratos(input_range)) # - - - - - - - - - - - - - - - End Of Functions - - - - - - - - - - - - - -# main()

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