Final answer:
The program provided asks the user for a negative number and calculates the product from -1 to that number. It iterates over the range in reverse, multiplying each successive negative number, considering the rule that the product of two negative numbers is positive.
Step-by-step explanation:
Program to Calculate Product of Negative Numbers
To write a program that asks the user for a negative number and prints out the product of all numbers from -1 to that number, we need to establish some ground rules based on multiplication properties:
- When two positive numbers multiply, the result is positive.
- When two negative numbers multiply, the result is also positive.
- When numbers with opposite signs multiply, the result is negative.
- The division of numbers follows the same sign rules as multiplication.
Focusing on multiplication, every time another negative number is multiplied to the product, the sign alternates. For example, multiplying -1 * -2 gives +2, but if another -1 is multiplied, the product becomes -2.
Here is a basic Python program to calculate such a product:
product = 1
user_input = int(input('Enter a negative number: '))
if user_input < 0:
for number in range(-1, user_input - 1, -1):
product *= number
print('Product is:', product)
else:
print('Please enter a negative number.')
This program multiplies all numbers from -1 to the user-input number. The looping construct for number in range(-1, user_input - 1, -1) iterates over each negative number, decrementing until it reaches the user-input number.