Keyboard Input -- Numbers

The "input" command is used to input information from the keyboard and assign it to a variable, as in:

mark = input("What mark did you get? ")

Optionally, you can print a statement and then wait for the keyboard input, as follows:

print "What mark did you get? "

mark = input()

If you were to print the answer by a number, as follows:

print (mark * 2)

...you would get an error, because Python is expecting a string (text) to be entered. To solve this problem, we must cast (convert) the string to an integer, as follows:

print (2 * int(mark))

If we wanted to enter a real number (float), we would cast its value as follows:

print (2 * float(mark))

Here is an example that prompts for and prints your birth year:

print ("What year were you born?")

birthYear = int(input())

print ("You were born in", birthYear)

Assignment

Write a program that prompts for your year of birth and the current year, then calculates and neatly outputs your age.

Save as "018.py".