Calling Methods Inside Classes in OOP in PHP

Some methods can be called inside others via $this. Let's look at an example. Suppose we have a class with a user and a method that returns a property:

php<?php
  class User {
    public $name;
    
    public function show() {
      return $this->name;
    }
  }
?>

Suppose we also have a method cape, which converts the first letter of a string to uppercase:

php<?php
  class User {
    public $name;
    
    public function show() {
      return $this->name;
    }
    
    public function cape($str) {
      return mb_strtoupper(mb_substr($str, 0, 1)) . mb_substr($str, 1);
    }
  }
?>

Let's use the method cape inside the method show:

php<?php
  class User {
    public $name;
    
    public function show() {
      return $this->cape($this->name);
    }
    
    public function cape($str) {
      return mb_strtoupper(mb_substr($str, 0, 1)) . mb_substr($str, 1);
    }
  }
?>