Function displays nothing after returning

Question

 import math


def erathosthene(n):
    
    for d in range(2, int(math.sqrt(n) + 0.5)):
        while n % d != 0:
            d =+ 1
        if n % d == 0:
            print('this number isn\'t prime')
            return False
        else:
            print('this number is prime')
            return True

erathosthene(35)

it literally display nothing and honestly idk why it display nothing

there's nothing after return in terminal

Also with 6, the loop doesn't generate any value, so nothing is returned from the method — azro, Jan 02 '22 at 15:44
An integer n is prime if d varying from 2 at √n n checks the condition: As long as it is not divisible by d, we increment the value of d. If n is divisible by d then n is not first. And of course, if n is not divisible by any of the values taken by d, then n is prime — swken999, Jan 02 '22 at 16:20

score 1 · Accepted Answer · answered Jan 02 '22 at 16:28

What you're doing is a primality test and the problems of your code are

let the for loop increase d, don't increase it by yourself too
if n is divisible by d then you end as it is not prime
if n is NOT divisible by the current d, that doesn't mean it is prime, you wait to wait
loop until sqrt(x)+1 not sqrt(x)+0.5, because for
add condition for numbers < 2

def erathosthene(n):
    if n < 2:
        return False
    for d in range(2, int(math.sqrt(n) + 1)):
        if n % d == 0:
            return False
    return True

Then call with a print so your code displays something

print(erathosthene(6))

For better implementation, you can see isPrime Function for Python Language for example

Function displays nothing after returning

1 Answers1