Input & Output

Real programs talk with people. The output half you already know: print() sends text out to the screen.

The input half uses input(). It pauses the program, waits for the person to type a line, and hands back what they typed as a string:

name = input("What is your name? ")
print(f"Hello, {name}!")

One thing to remember: input() always returns a string, even if the person types digits. To do math with it you convert first, with int(...) or float(...):

age_text = input("Your age? ")   # e.g. "20", a string
age = int(age_text)              # now the number 20
print(age + 1)

Why we will use functions here instead

This lesson runs inside an auto-grader that has no keyboard waiting on the other end, so calling input() would just hang. The professional habit anyway is to keep the talking-to-humans part separate from the logic. So we wrap the logic in a function that takes the value as a parameter, and the real input would simply be passed in:

def greet(name):
    return f"Hello, {name}!"

print(greet("Ada"))   # Hello, Ada!
# In a real app:  greet(input("Name? "))