representing a basic calculator using python

basic_calculator.py

"""
A calculator program that tells the computer to ask a user for two numbers to calculate, then returns the answer
from the user's input. Python automatically considers what the user types in as a string.

This text and the text above is surrounded by 3 double quotes, which makes it a "docstring".
Docstrings are one way to convey what is happening in a program, or what is supposed to happen, they do not have a program "do" anything.
"""

# Any line that starts with a pound sign (#) is known as a comment, Python knows to ignore comments.
# Comments are useful for explaining what you are doing in a program to yourself or someone else who might 
# be working on the same program.

print("Please give me a number")
number1 = raw_input()             # here's our first variable

print("Please give me another number")
number2 = raw_input()             # here's our second variable

# We need to convert the value of the variables to a whole number, so Python can calculate the numbers
number1 = int(number1)
number2 = int(number2)

print("What operation would you like me to do with the two numbers?")
operation = raw_input()

# Below is our condition statements, or IF and THEN statements
# notice the indentations, these are called blocks of code
# anything that is indented under a statement, is part of that first statement

# checking if the input from the user is addition
if operation == "+":
  answer = number1 + number2

# checking if the input from the user is subtraction
elif operation == "-":
  answer = number1 - number2

# checking if the input from the user is multiplication
elif operation == "*":
  answer = number1 - number2
  
# checking if the input from the user is division
elif operation == "/":
  answer = number1 / number2
  
# Now, to print the answer
print(answer)

### NOTE:
# For the first part of the program, we could shorten the amount we type by combining lines of code.
# For instance, lines 13 - 21 can be rewritten as:

# number1 = int(raw_input("Please give me a number"))
# number2 = int(raw_input("Please give me another number"))

# We'd get the program to do the same thing, only with fewer lines of code.
# Remember, engineers are concerned with building things efficiently!