def main():
    print("Welcome to the Calculator")
    command = input("Select command: [ + ] [ - ] [ * ] [ / ] \nType exit if u want exit \n")
    match command: #выбор команд
        case "+":
            summ()
        case "*":
            multiplication()
        case "-":
            minus()
        case "exit":
            exit
        case _:
            print(KeyError("Incorrect"))
            main()
def summ():
    print("Enter number(s) to sum, enter space to calculate")
    total = 0
    while True:
        num_input = input()
        if num_input == " " or num_input == "":
            print (f"Total summ = {total}")
            main()
        try: 
            number = float(num_input)
            total += number
            print(f"Total summ = {total}")
        except ValueError:
            print("Error, enter correct number")
def minus():
    print("Enter number(s) to minus, enter spase to calculate")
    total = 0
    while True:
        num_input = input()
        if num_input == " ":
            print(total)
            main()
        try:
            number = float(num_input)
            total -= number
            print(f"Total minus = {total}")
        except ValueError:
            print("Error, enter correct number")
def multiplication():
    print("Enter number to multiplication, enter space to calculate")
    total = 1
    while True:
        num_input = input()
        if num_input == " ":
            print (total)
            main()
        try: 
            number = float(num_input)
            total *= number
            print(f"Total multiplication = {total}")
        except ValueError:
            print("Error, enter correct number")

if __name__ == "__main__":
    main() #запуск функции main, основа программы