PHP for循环仅运行一次

Question

I've been taking the php course from code academy. In one of the exercises, i've tried to implement a conditional function, where it would take a parameter for how many times the function would run. Unfortunately it is not running. I'm trying to run the bark() twice with bark(2). It's only echoing once. I have tried a "do while", "if" and "for". None worked. Why is that?

<?php
   class Dog{
        public $numLegs = 4;
        public $name;
        public $speak = "Woof!";
  public function bark($up){
      $counter = 0;
      for($counter; $counter!=$up;$counter++){
      return $this->speak;
      }
  }

  public function greet(){
      return "Hello " . $this->name . "!" . "<br />";
  }

   public function __construct($name){
       $this->name = $name;
    }
   }
   $dog1 = new Dog("Barker");
   $dog2 = new Dog("Amigo");

   echo $dog1 -> bark(2);
   echo $dog2 -> name;
?>

Answer 1

You are returning $this->speak , as soon as you return a value the entire function stops execution.

You could do something like:

public function bark($up){
    $counter = 0;
    $return = '';
    for($counter; $counter<$up;$counter++){
        $return .= $this->speak;
    }

    return $return;
}

Answer 2

To add another solution, without using for at all using array_fill() to create an array of the wanted size and content (since it is always the same text) and then simply implode() to receive a String as result.

public function bark($up){
    return implode(array_fill(1, $up, $this->speak));
}

Answer 3

What you want to do is run the bark function in a for loop, not have a for loop in the bark function.

public function bark(){
  return $this->speak;
}

for($i = 0; $i < 2; $i++){
  echo $dog1 -> bark();
}

The problem with looping inside the bark function mostly comes from the fact that you lose a lot of flexibility.

You could echo right in there, but outputting data from an object's method is far from ideal. What if you need to perform some kind of logic on the output?

You could also concatenate within the function, but then again, what if you need to format the output? Then you'd have to split the output again, which defeats the purpose.

Answer 4

return inside the for loop exits from the bark function. So the dog barks only once.

public function bark($up){
      $counter = 0;
      for($counter; $counter!=$up;$counter++){
         echo $this->speak;
      }
  }

$dog1 -> bark(2);

Answer 5

You have to change these lines:

return $this->speak;

To:

echo $this->speak;

And

echo $dog1->bark(2);

To:

dog1->bark(2);

The return statement stops immediatly the method, this is the reason you are getting only one echo