Using input in a function and using variables

December 10, 2023

I am trying to make a calculator as homework and using functions in it is necessary. I wrote multiple functions for dividing, multiplying etc. The problem is getting user input.

I wrote the gui(a, b) function that gets a and b as a float input. But when I try to use it with other functions I get the “a and b not defined” error.

Here is the code:

def top(a, b):
    a, b = gui()
    return a + b
def cik(a, b):
    return a - b
def bol(a, b):
    return a / b
def carp(a, b):
    return a * b
def gui(a, b):
    a = float(input("1. Sayıyı Giriniz:"))
    b = float(input("2. Sayıyı Giriniz:"))
    return a, b
while True:
    print("İşlemler:")
    print("1: Toplama")
    print("2: Çıkarma")
    print("3: Çarpma")
    print("4: Bölme")
    print("5: ÇIKIŞ")
    islem = input("İşlem Seçiniz:")
    if islem in (1, 2, 3, 4):
        if islem == 1:
            gui(a, b)
            print(a, "+", b, "=", top(a,b))
        elif islem == "2":
            gui(a, b)
            print(a, "-", b, "=", cik(a,b))
        elif islem == "3":
            gui(a, b)
            print(a, "*", b, "=", carp(a,b))
        elif islem == "4":
            gui(a, b)
            print(a, "/", b, "=", bol(a,b))
    elif islem == 5:
        print("ÇIKIŞ YAPILIYOR...")
        break
    else:
        print("Geçersiz İşlem Numarası!!!")

>Solution :

Define gui without the parameters, don’t pass a and b to gui because you did not define them. Instead assign gui‘s returned values to a and b, respectively. Just like you did at top.

def top(a, b):
    a, b = gui()
    return a + b
def cik(a, b):
    return a - b
def bol(a, b):
    return a / b
def carp(a, b):
    return a * b
def gui():
    a = float(input("1. Sayıyı Giriniz:"))
    b = float(input("2. Sayıyı Giriniz:"))
    return a, b
while True:
    print("İşlemler:")
    print("1: Toplama")
    print("2: Çıkarma")
    print("3: Çarpma")
    print("4: Bölme")
    print("5: ÇIKIŞ")
    islem = input("İşlem Seçiniz:")
    if islem in (1, 2, 3, 4):
        if islem == 1:
            a, b = gui()
            print(a, "+", b, "=", top(a,b))
        elif islem == "2":
            a, b = gui()
            print(a, "-", b, "=", cik(a,b))
        elif islem == "3":
            a, b = gui()
            print(a, "*", b, "=", carp(a,b))
        elif islem == "4":
            a, b = gui()
            print(a, "/", b, "=", bol(a,b))
    elif islem == 5:
        print("ÇIKIŞ YAPILIYOR...")
        break
    else:
        print("Geçersiz İşlem Numarası!!!")