Exception handling

[Calli]

A simple python calculator i wrote

#!/usr/bin/python

print("Please select your desire operation")
print("1. Addition")
print("2. Subtraction")
print("3. Multiplication")
print("4. Division")

#this function is to add two numbers
def add(a,b):
    x = a + b
    return x
#this function is to subtract the two numbers
def subs(a,b):
    x = a - b
    return x
#this function is for multiplication
def muls(a,b):
    x = a * b
    return x
#this function is for division
def divs(a,b):
    x = a / b
    return x

try:
    insert = int(input("Enter your choice: "))
except (ValueError,KeyboardInterrupt):
    print ("You must type the number between 1 to 4")
else:
    if insert == 1:
        a = int(input("Enter the first number to add: "))
        b = int(input("Enter the second number to add: "))
        print (add(a,b))
    elif insert == 2:
        a = int(input("Enter the first number to subtract: "))
        b = int(input("Enter the second number to subtract: "))
        print (subs(a,b))
    elif insert == 3:
        a = int(input("Enter the first number to multiply: "))
        b = int(input("Enter the second number to multiply: "))
        print (muls(a,b))
    elif insert == 4:
        a = int(input("Enter the first number to divide: "))
        b = int(input("Enter the second number to divide: "))
        print (muls(a,b))
    else:
        print ("Some unexpected error occurred")

The first exception works like charm but when i am inside the if loop the program output's the error

Please select your desire operation
1. Addition
2. Subtraction
3. Multiplication
4. Division
Enter your choice: 1
Enter the first number to add: 2
Enter the second number to add: abcd
Traceback (most recent call last):
  File "Calculator3.py", line 33, in <module>
    b = int(input("Enter the second number to add: "))
ValueError: invalid literal for int() with base 10: 'abcd'

How do i write a program which will accept exception error inside the if loop?

[deanhystad]

try:
    # code
except ValueError:
    # exception code

The tricky part is what do you put in the #code and #exception code parts.

You could use an exception handler to make sure all inputs are integers. This one keeps asking until you enter an integer.

def get_input(prompt):
    while True:
        try:
            return int(input(prompt))
        except ValueError:
            print('Inputs must be integer')

Or you could put the try/except around your entire code and just print "Oopsy! Some error occurred"

You have another exception to check for (ZeroDivisionError).

[Calli]

i will try to put the try/except around my entire code thank you