Question

Write a program that lets a user enter N and that outputs N! (N factorial, meaning N*(N-1)*(N-2)*...*2*1). Hint: Initialize a variable total to N (where N is input), and use a loop variable i that counts from total-1 down to 1. Compare your output with some of these answers: 1:1, 2:2, 3:6, 4:24, 5:120, 8:40320.

Given sample code:
total = int(input()) # Read user-entered number
while i ? ??:#
Multiply total * (i-1)
# Decrement i

Answer 1

To calculate the factorial of a number, you can use a loop to multiply the numbers together. Here is an example code that does that.

Step-by-step explanation:

To write a program that calculates the factorial of a number, you can use a loop to iterate through the numbers from N down to 1 and multiply them together. Here is an example:

total = int(input()) # Read user-entered number

i = total - 1
while i > 1:
total *= i
i -= 1

print(total)

In this code, the variable 'total' is initialized with the user-entered number, and the loop variable 'i' is used to count down from 'total-1' to 1. 'total' is continuously multiplied by 'i' in each iteration of the loop. Finally, the result is printed.

Answer 2

A program in Python to calculate N factorial uses a while loop to multiply a total by a decrementing loop variable 'i' from N-1 to 1, outputting the result after the loop.

Step-by-step explanation:

To calculate N factorial (N!), you can complete the provided code by initializing a loop variable i to N and then use a while loop to iterate from N-1 down to 1. In each iteration, you'll multiply the current total by i and then decrement i by 1.

A complete program in Python could look like this:

total = int(input("Enter N: "))
# Check if the entered number is valid for factorial
if total < 0:
print("Factorial does not exist for negative numbers.")
elif total == 0:
print("1")
else:
i = total
while i > 1:
i -= 1
total *= i
print(total)

This program reads an integer value for N, then checks if it is a non-negative number. Assuming it is, the program enters the while loop, multiplies the total by the current value of i, and decreases i until it reaches 1. After the loop finishes, it outputs the calculated factorial total.