<?php
abstract class R{
abstract function r();
}
final class A extends R{
public function r(){
echo "a";
}
public function a()
{
return $this->r();
}
}
class B extends R{
public function r(){
echo "b";
}
public function b()
{
return $this->r();
}
}
class C extends R{
public function r(){
echo "c";
}
public function c()
{
return $this->r();
}
}
class D extends B{
public function r(){
return $this->b();
}
}
$a = new A();
$b = new B();
$b = new C();
$b = new D();
function forLoopFirst() {
return forLoopSecond();
}
function forLoopSecond() {
return forLoopFirst();
}
forLoopFirst()