PHP：如何从父类调用子类的函数 [英] PHP: How to call function of a child class from parent class

问题描述

如何从父类调用子类的函数？
考虑一下：

How do i call a function of a child class from parent class? Consider this:

class whale
{
  function __construct()
  {
    // some code here
  }

  function myfunc()
  {
  // how do i call the "test" function of fish class here??
  }
}

class fish extends whale
{
  function __construct()
  {
    parent::construct();
  }

  function test()
  {
    echo "So you managed to call me !!";
  }

}

推荐答案

这就是抽象类的用途。一个抽象类基本上说：无论谁继承我，都必须有这个函数（或这些函数）。

That's what abstract classes are for. An abstract class basically says: Whoever is inheriting from me, must have this function (or these functions).

abstract class whale
{

  function __construct()
  {
    // some code here
  }

  function myfunc()
  {
    $this->test();
  }

  abstract function test();
}


class fish extends whale
{
  function __construct()
  {
    parent::__construct();
  }

  function test()
  {
    echo "So you managed to call me !!";
  }

}


$fish = new fish();
$fish->test();
$fish->myfunc();

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