Sequence, input & output

A program runs in order

• A program is a list of steps.
• Python runs them from top to bottom, one at a time.
• This order is called sequence — the first idea in the syllabus.

print("Wake up")
print("Brush teeth")
print("Go to school")

OUTPUT becomes print()

• In the exam, OUTPUT shows something on the screen.
• In Python, that is print().
• The text inside the quotes is printed, then a new line starts.

print("Hello, world!")
print("IGCSE Computer Science")

INPUT becomes input()

• In the exam, INPUT reads what the user types.
• In Python, that is input().
• It always gives back a string (text), even if the user types digits.

name = input()
print("Hello, " + name)

Turn input into a number

• input() gives text, so "5" is not the number 5.
• Wrap it with int() to get a whole number.
• Now you can do maths with it.

age = int(input())
print(age + 1)

In the exam: pseudocode

• The same idea in Cambridge pseudocode uses INPUT and OUTPUT.

OUTPUT "What is your name?"
INPUT Name
OUTPUT "Hello, ", Name

Common mistakes

• Statements run from top to bottom, in the order you write them.
• input() gives back text (a string); use int(...) when you need a number.

Now you try

• Use print() to show output.
• Use input() to read a line — leave the brackets empty here.
• Press Check answer to test your code.