Several example codes

Program Overview

This Python program reads multiple even numbers greater than 2 and checks whether each can be expressed as the sum of two prime numbers.
The program continues until the user chooses to exit.

Python Code:

def is_prime(num: int) -> bool:
    if num < 2:
        return False
    for i in range(2, int(num**0.5) + 1):
        if num % i == 0:
            return False
    return True

def goldbach_pair(even_num: int):
    for i in range(2, even_num):
        if is_prime(i) and is_prime(even_num - i):
            return (i, even_num - i)
    return None

def main():
    while True:
        try:
            n = int(input("Enter an even number greater than 2 (or 0 to exit): "))
            if n == 0:
                print("Exiting program.")
                break
            if n <= 2 or n % 2 != 0:
                print("Number must be even and greater than 2.")
                continue
            pair = goldbach_pair(n)
            if pair:
                print(f"{n} = {pair[0]} + {pair[1]}")
            else:
                print(f"No prime pair found for {n}.")
        except ValueError:
            print("Please enter a valid integer.")

Sample Output:

Enter an even number greater than 2 (or 0 to exit): 28  
28 = 5 + 23  
Enter an even number greater than 2 (or 0 to exit): 44  
44 = 3 + 41  
Enter an even number greater than 2 (or 0 to exit): 0  
Exiting program.