How to not make the program restart after a value error?

November 18, 2022

So I recently started coding and just learned about ‘try’ and ‘except’ for ‘ValueError’. I made this calculator but it restarts if you don’t input an int on the ‘second’ input. How do I make it ask for pnly the ‘second’ variable instead of asking for the first one again?

while True:
    try:
        first = int(input("First: "))
        second = int(input("Second: "))
        sum = first + second
        print(f"Sum: {sum}")
        break
    except ValueError:
        print("I didn't understand that")

I tried this but it just asked for the second variable then restarted the program

while True:
    try:
        first = int(input("First: "))
        second = int(input("Second: "))
        sum = first + second
        print(f"Sum: {sum}")
        break
    except ValueError:
        print("I didn't understand that")
        int(input("Second: "))

>Solution :

Use a separate while with try/except blocks for the two prompts. And since you are doing the same thing multiple times, put the common part in a function

def get_input(prompt, cast_to=int):
    while True:
        try:
            return cast_to(input(prompt))
        except ValueError:
            print("I didn't understand that")

first = get_input("First: ")
second = get_input("Second: ")
sum = first + second
print(f"Sum {sum}")