In Chapter 8, the loop-and-a-half was explained. The final code for the example that was presented is given below, and I made the remark that there is still something ugly about this code, namely the fact that if x is smaller than zero or higher than 1000, the code still asks for y even when it can know that it has to ask a new value for x. I also remarked that you can resolve this in an easy way by using a function. Create a function and insert it in this code, so that this issue gets fixed. Also get rid of the exit() and thus the possible ugly output by introducing a main() function.

from sys import exit

while True:
    x = int( input( "Enter number 1: " ) )
    if x == 0:
        break
    y = int( input( "Enter number 2: " ) )
    if y == 0:
        break
    if (x < 0 or x > 1000) or (y < 0 or y > 1000):
        print( "The numbers should be between 0 and 1000" )
        continue
    if x%y == 0 or y%x == 0:
        print( "Error: the numbers cannot be dividers" )
        exit()
    print( "Multiplication of", x, "and", y, "gives", x * y )

print( "Goodbye!" )

Assignment

Write a function get_valid_number that takes a prompt (str). The function must keep asking for an integer using the given prompt, until the user enters a value between 0 and 1000 (inclusive); for every value outside that range, print The numbers should be between 0 and 1000 before asking again. The function must return the validated integer (int).

Rewrite the code above into a function main that takes no arguments, using get_valid_number to fix the issue described above. Also get rid of the exit() by using return instead.

Example

>>> get_valid_number("Enter number 1: ")
Enter number 1: -42
The numbers should be between 0 and 1000
Enter number 1: 314
314

>>> main()
Enter number 1: -5
The numbers should be between 0 and 1000
Enter number 1: 250
Enter number 2: 999
Multiplication of 250 and 999 gives 249750
Enter number 1: 0
Goodbye!