如何检查命令是否已经执行

Question

Here's the problem : I don't know how to write the script so that if I type more than once start or stop the script will print something like "Already running" or "Not running"

running = True
print("Type help for a list of commands. ")
while running :
    user=input("> ")
    user_input=user.upper()
    if user_input==("HELP"):
        print(f"""Type start to start the car.
Type stop to stop the car.
Type quit to quit the game.""")
    elif user_input==("START"):
        print("You started the car. ")
    elif user_input==("STOP"):
        print("You stopped the car. ")
    elif user_input==("QUIT"):
        print("You stopped the game.")
        running=False
    elif user_input!=("START") and user_input!=("STOP") and user_input!=("QUIT"):
        print("I don't understand that. ")

Example:

 >start
You started the car.
 >start
Car is already running.
 >stop
You stopped the car.
 >stop
Car isn't turned on.

Answer 1

First of all, if you want to stop the car, you must start it first, right?

Make one global variable—let's call it started —and set it to False . Now, when we want to "start" the car, first we need to check:

elif user_input==("START"):
    if started:
        print("Car is already running")
    else:
        print("You started the car")
        started = True

Then just do the similar statement with stopping: if started is True , then it means your car is running and you can stop it. Set started to False and print the message that car is stopped. Otherwise, you didn't even turn on the car.

PS Be careful: declare and initialize started before your while loop!