Reading inputs from the user

Now, we will discuss a simple program where we ask the user to enter two numbers and the program returns the sum of two numbers. For now, we are going to pretend that the user always provides a valid input.

In Python, user input to a Python program can be provided using the input() function (https://docs.python.org/3/library/functions.html#input):

    var = input("Enter the first number: ")

In the preceding example, we are making use of the input() function to seek the user's input of the number. The input() function takes the prompt ("Enter the first number: ") as an argument and returns the user input. In this example, the user input is stored in the variable, var. In order to add two numbers, we make use of the input() function to request user to provide two numbers as input:

    var1 = input("Enter the first number: ") 
    var2 = input("Enter the second number: ") 
    total = int(var1) + int(var2) 
    print("The sum is %d" % total)

We are making use of the...