Basic calculator program in python

Question

I just wrote a simple calculator script in python, generally python should recognize the (-)minus,(*)multiplication,(/)divide sign by default but while considering this script it's fails to identify the signs. please leave your comments to clear me...

#! /usr/bin/python

print("1: ADDITION")
print("2: SUBTRACTION")
print("3: MULTIPLICATION")
print("4: DIVISION")

CHOICE = raw_input("Enter the Numbers:")

if CHOICE == "1":
    a = raw_input("Enter the value of a:")
    b = raw_input("Enter the value of b:")
    c = a + b
    print c

elif CHOICE == "2":
    a = raw_input("Enter the value of a:")
    b = raw_input("Enter the value of b:")
    c = a - b
    print c

elif CHOICE == "3":
    a = raw_input("Enter the value of a:")
    b = raw_input("Enter the value of b:")
    c = a * b
    print c

elif CHOICE == "4":
    a = raw_input("Enter the value of a:")
    b = raw_input("Enter the value of b:")
    c = a / b
    print c

else: 
 print "Invalid Number"
 print "\n"

I don't understand the question. You don't process signs in this script, you process numbers. (Although there is a separate issue to do with the types of a and b.) — Daniel Roseman, Nov 22 '12 at 09:09

billwild · Answer 1 · 2012-11-22T09:40:30.830

5

You need to change your inputs, strings to integer or float. Since, there is division you are better change it to float.

a=int(raw_input("Enter the value of a:"))
a=float(raw_input("Enter the value of a:"))

edited Nov 22 '12 at 09:40

answered Nov 22 '12 at 09:13

billwild

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score 4 · Answer 2 · answered Nov 22 '12 at 09:15

When you get the input it is a string. The + operator is defined for strings, which is why it works but the others don't. I suggest using a helper function to safely get an integer (if you are doing integer arithmetic).

def get_int(prompt):
    while True:
        try:
            return int(raw_input(prompt))
        except ValueError, e:
            print "Invalid input"

a = get_int("Enter the value of a: ")

score 1 · Answer 3 · answered Nov 22 '12 at 09:36

Billwild said u should change to make your variables integers. But why not float. It is not important if it is integer or float it must be number type. Raw_input takes any input like string.

a=float(raw_input('Enter the value of a: '))

Or for Tim's aproach

def get_float(prompt):
    while True:
        try:
            return float(raw_input(prompt))
        except ValueError, e:
            print "Invalid input"

a = get_float("Enter the value of a: ")

You can always convert result to float or to int or back. It is just matter what kind of calculator u are programming.

You are right - Since there is division it is better if you convert to float. — billwild, Nov 22 '12 at 09:38

Basic calculator program in python

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