PHP实现的栈数据结构示例【入栈、出栈、遍历栈】

<?phpclass Stack{  const MAXSIZE = 4;// 栈最大容量  private $top = -1;  private $stack = array();// 利用数组存储数据  public function __construct(){    $this->stack = array();  }  // 入栈  public function push($ele){    if ($this->top >= self::MAXSIZE-1){      echo 'stack is full...';      return false;    }    $this->stack[++$this->top] = $ele;// 此处必须是++i，先计算再使用  }  // 出栈，返回出栈元素  public function pop(){    if ($this->top == -1){      echo 'stack is empty...';      return false;    }    $ele = $this->stack[$this->top];    unset($this->stack[$this->top--]);// 此处必须是i--，先使用再计算（注意出栈和入栈的区别）    return $ele;  }  // 遍历栈  public function show(){    if ($this->top == -1){      echo 'stack is empty...';      return false;    }    for($i=$this->top; $i>-1; $i--){      echo $this->stack[$i].'<br/>';    }  }}$stack = new Stack;$stack->push(1);$stack->push(2);$stack->push(3);$stack->push(4);//print_r($stack);$stack->show();$a = $stack->pop();$a = $stack->pop();$a = $stack->pop();$stack->show();

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