The provided Python program is designed to find the prime factors of a given number. It utilizes a function called
prime_factors() to accomplish this task. The program takes a number as input, either from the user or as a command-line argument, and proceeds to calculate the prime factors.
Write a Python program that prompts the user to enter a positive integer and then finds and displays the prime factors of that number.
- The program should validate that the input is a positive integer. If the input is invalid, display an error message and prompt the user again until a valid input is provided.
- The program should calculate and display all the prime factors of the given number.
- The prime factors should be displayed in ascending order.
Python Program to Find the Prime Factors of a Number
def prime_factors(n): factors =  i = 2 while i * i <= n: if n % i: i += 1 else: n //= i factors.append(i) if n > 1: factors.append(n) return factors # Example usage number = int(input("Enter a number: ")) factors = prime_factors(number) print("Prime factors of", number, "are:", factors)
How it Work
The Python program to find the prime factors of a given number works as follows:
- Prompt the user to enter a positive integer.
- Validate the input to ensure it is a positive integer. If the input is invalid (not a positive integer), display an error message and prompt the user again until a valid input is provided.
- Define a function called
prime_factors(n)that takes the input number
nas a parameter.
- Initialize an empty list called
factorsto store the prime factors.
- Initialize a variable
- Use a while loop that runs until
i * iis greater than
n. This optimization ensures that we only check potential factors up to the square root of
- Inside the while loop, check if
nis divisible evenly by
i. If it is, divide
factorslist, and continue to the next iteration of the loop.
nis not divisible by
iby 1 and continue to the next iteration of the loop.
- After the while loop, check if
nis greater than 1. If it is, it means
nitself is a prime number, so append it to the
- Return the
- Call the
prime_factors()function with the input number and store the result in a variable.
- Print the prime factors of the given number.
The program follows this algorithm to find the prime factors of the input number. It utilizes a while loop, division, and iteration to determine the prime factors. The output is then displayed to the user.
Explanation: The user enters the number 56. The prime factors of 56 are 2, 2, 2, and 7. The program calculates and displays the prime factors in ascending order.