mainnew.py

PrimeNumberFinder/main.py

@@ -1,39 +1,20 @@
-# Prime Number Finder.
-# It uses the algorithm "Sieve of Eratosthenes" to find all prime numbers
-# smaller or equal to a given number n.
-# Read more: https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
+num = int(input("Enter number:"))
 
-__author__ = 'codinglukas'
+# To take input from the user
 
 
-def compute_primes(n):
-    """
-    First we create a boolean array of length n and all entries
-    are set to true. In the end the i-th entry will be true
-    if and only if i is a prime number.
-    :param n:
-    :return prime numbers <= n:
-    """
-    primes = [True for i in range(n + 1)]
-    p = 2
-    while p * p <= n:
-        # If primes[p] is not changed, then it is a prime
-        if primes[p]:
-            # Update all multiples of p too
-            for i in range(p * 2, n + 1, p):
-                primes[i] = False
-        p += 1
-    primes[0] = False
-    primes[1] = False
-
-    result = []
-    for p in range(n + 1):
-        if primes[p]:
-            result.append(p)
-
-    return result
-
-
-if __name__ == '__main__':
-    n = 30
-    print(compute_primes(n))
+# prime numbers are greater than 1
+if num > 1:
+   # check for factors
+   for i in range(2,num):
+       if (num % i) == 0:
+           print(num,"is not a prime number")
+           print(i,"times",num//i,"is",num)
+           break
+   else:
+       print(num,"is a prime number")
+
+# if input number is less than
+# or equal to 1, it is not prime
+else:
+   print(num,"is not a prime number")