How to decrease a variable to zero?-CodePudding

I have a variable inputted by any user to my program. The task I cannot get to work is I want the variable to decrease from the input value to 0 over the course of a variable time (also input by the user). In pseudocode that would be something akin to:

x = time_variable
y = decreasing_variable
z = amount_of_decrease_of_y
while i < x:
    y = y - z;

I have tried writing the code, but it doesn't work properly:

time_of_activity = float(input('How long should health decrease in hours? '))
time_of_activity = time_of_activity * 60 * 60
health = float(input('How much is starting health? '))
X = health / time_of_activity 

def healthdecrease():
   i = 1
   while i<(time_of_activity):
    time.sleep(1)
    i =1
    health = health - X

decrease_of_health = threading.Thread(target=healthdecrease)
decrease_of_health.start()

That is the code I have so far. It seems to be missing something, but I can't figure it out.

CodePudding user response：

You are not calling the healthdecrease function correctly. It should be like this:

decrease_of_health = threading.Thread(target=healthdecrease())

I guess you can just do it like this:
def healthdecrease():
 while(health):
   health -= x

CodePudding user response：

For the most part the logic of the code is correct, however there was no indication to python that health is a global variable. This must be done explicitly in the health_decrease method so that it uses the existing global variable rather than creating a new, local one.
Other than that, some of the formatting (more specifically, the indentation) was off.
Lastly, I added a max() component when subtracting decrement from health to ensure the value never goes below 0 due to floating point rounding errors.

Here is a functional code sample (without the threading):

import time

time_of_activity = float(input('How long should health decrease for in seconds? '))

health = float(input('What is the starting health? '))
decrement = health / time_of_activity 

def health_decrease():
    global health
    i = 1
    while i <= time_of_activity:
        time.sleep(1)
        i  = 1
        health = max(health - decrement, 0)

health_decrease()