PHP - 在 class 中调用公共 function 不起作用

Question

I'm new to working with classes in PHP

When I try to call $example->vars(); in the following class, the method changeVar() within this method vars() doesn't work. Why can't I call this?

<?php

class example {

    private $var1;

    public function __construct($var1) {
        $this->var1 = $var1;
    }
    
    public function changeVar() {
        $var1 = $this->var1;
        $var1 = $var1 + 1;
        return $var1;
    }
    
    public function vars() {
        $var1 = $this->var1;
        
        $var1 = 2;
        $var1 = $this->var1;
        echo "<br>made it here<br>";
        $var1 = changeVar(); // Calls function changeVar() from above. This step doesn't work?
        return $var1;
    }
}


$example = new example(1);
echo $example->changeVar(); // Echos 2
echo $example->vars(); // Should echo 3?
?> 

Answer 1

You need to call it like $this->changeVar() inside class