← PHP theorytheory 0/50 · 0%

level 1

Curious · 0 XP

streak

perfect

badges

100 XP to Apprentice

OOP · easy

13. Visibility Modifiers

Controlling access to members.

1 min read2 questionsup to 50 XPtopic 13/50

Read in another language

AI translates the explanation and quiz text while preserving code and answer scoring.

public members are accessible from anywhere, protected members only from the class and its subclasses, and private members only from within the declaring class itself. Choosing the narrowest visibility that works enforces encapsulation.

Since PHP 7.4, typed properties can also be declared readonly-adjacent via visibility plus type hints for safer APIs.

How to study this topic

1. Read the explanation once end to end, skipping the code.
2. Re-read the code snippets and say out loud what each line does.
3. Answer the quiz without scrolling back — that is the real check.
4. Read every explanation, even for the answers you got right.

Scoring

· Up to 30 XP from quiz accuracy.
· +15 XP for a perfect first attempt.
· +5 XP while a 3-day streak is running.
· 75% or higher marks the topic complete.

Badges

First light

Pass your first topic

Sharp shooter

3 perfect first-try quizzes

On a roll

Study 3 days in a row

Week warrior

Study 7 days in a row

Grinder

Earn 500 XP

Deep diver

Earn 1500 XP