CyberStars

Input

Until now, all the values in our programs were written by us, the programmer. We chose name = "Tommy Vercetti", we chose age = 42. But what if we want the user to choose? What if we want the program to ask us something and react based on what we typed?

This is where input() comes in

name = input()
print(f"Hello, {name}!")

We run this code, type something (for example Lance) and press Enter. The program will display

Hello, Lance!

The program stopped and waited for us. The moment Python sees input(), it stops the program and waits for the user to type something. After we press Enter, whatever we typed gets stored in the variable name

We can also give the user a hint about what we want them to type

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

That little message inside input("...") is shown to the user before the program waits. It’s called a prompt

Now, here is something really important. Run this code

age = input("Your age: ")
next_year = age + 1
print(next_year)

You will get an error. Why? Because input() always gives back a string, even if the user types numbers. So age is "18" (text), not 18 (number). And we cannot do "18" + 1, since one is text and the other is a number

To fix it, we tell Python: "hey, take this text and turn it into a number"

age = int(input("Your age: "))
next_year = age + 1
print(next_year)

int() is a function that converts text into an integer (a whole number). Now age is really 18, and 18 + 1 = 19 works perfectly

If the user typed something with decimals like 1.75, we’d use float() instead

height = float(input("Your height: "))
print(height)

Mission: Crew Check-In

The space station registers every new crew member. Write a program that asks for the crew member's name, then their age, and prints a welcome message.

Remember that input() always gives back a string, so you must turn the age into a number with int() before you can add 1 to it.

Input:

  • the crew member's name
  • the crew member's age

Output

One line: Welcome aboard, then the name, then ! You are the age, then . Next year you will be the age plus one, then a .

Example

If the user types

Cortez
60

the program should print

Welcome aboard, Cortez! You are 60. Next year you will be 61.