projekt

 1"""
 2Test for primality.
 3
 4This file consists of two methods for determination of primality
 5
 6First is ''primes_sieve()''
 7Deterministic method of finding a prime number.
 8Method is more is more suited for creating list of primes.
 9
10Second function ''is_prime''
11also deterministic function
12is designed for faster operation when searching for primality of given number.
13"""
14
15import math
16
17
18def primes_sieve(limit: int) -> bool:
19    """
20    Input variable vstup greater than 100 is tested for primality.
21
22    List of prime numbers is generated up to the upper limit
23    given by the parameter ``limit``.
24    Function then tests if ``limit`` is in the generated list.
25
26    :param limit: number that is tested for primality
27    :return: function returns true if parameter limit is prime number
28    """
29    limitn = limit + 1
30    primes = [i for i in range(2, limitn)]
31
32    for i in primes:
33        factors = range(i, limitn, i)
34        for f in factors[1:]:
35            if f in primes:
36                primes.remove(f)
37    if limit in primes:
38        return True
39    else:
40        return False
41
42
43def is_prime(vstup: int) -> bool:
44    """
45    Input variable vstup lower than 100 is tested for primality.
46
47    Function reduces number of modulators to save time.
48    Python math library needs to imported before deployment of this function.
49
50    :param vstup: number that is tested for primality
51    :return: function returns true if vstup is primal number
52    """
53    if vstup <= 1:
54        return False
55    if vstup % 2 == 0:
56        return vstup == 2
57
58    max_div = math.floor(math.sqrt(vstup))
59    for i in range(3, 1 + max_div, 2):
60        if vstup % i == 0:
61            return False
62    return True
63
64
65def main(vstup):
66    """Choose an algorithm for primality test."""
67    if vstup >= 100:
68        if is_prime(vstup):
69            print("Your number is prime.")
70        else:
71            print("Your number isn't prime.")
72    elif 100 > vstup > 1:
73        if primes_sieve(vstup):
74            print("Your number is prime. Sieve method was used.")
75        else:
76            print("Your number isn't prime. Sieve method was used.")
77    else:
78        print("Please enter a positive number!")
79
80
81if __name__ == '__main__':
82    try:
83        main(int(input("Please enter a number: ")))
84    except ValueError:
85        print("Please enter a positive number!")