php - 簡單工廠模式中的問題，總是報錯

PHPzhong2017-04-11 09:53:49 0 3 101

//接口

interface calc{

public function getResult();

}

//運算類

class Operation{

protected $num1=0;

protected $num2=0;

protected $result=0;

public function setNum($num1,$num2){

$this->num1 = $num1;

$this->num2 = $num2;

}

}

//四則運算類

class OperAdd extends Operation implements calc{

public function getResult(){

return $this->result=$this->num1+$this->num2;

}

}

class OperSub extends Operation implements calc{

public function getResult(){

return $this->result=$this->num1-$this->num2;

}

}

class OperMul extends Operation implements calc{

public function getResult(){

return $this->result=$this->num1*$this->num2;

}

}

class Operp extends Operation implements calc{

public function getResult(){

if(intval($this->num2)==0){

return $this->result="被除數不能為‘0’！";

}else{

return $this->result=$this->num1/$this->num2;

}

}

}

class OperFactory{

private static $obj;

public static function createrOper($type){

try {

switch ($type){

case'+';

self::$obj = new OperAdd();

break;

case'-';

self::$obj = new OperSub();

break;

case'*';

self::$obj = new OperMul();

break;

case '/':

self::$obj = new Operp();

break;

default:

throw new Exception('unknow type');

}

} catch (Exception $e) {

echo $e->getMessage();

}

}

}

$obj = OperFactory::createrOper('+');

$obj->setNum(2,2);

echo $obj->getResult();

// $obj= OperFactory::createrOper('+');

// $obj->setNum(2, 2);

// var_dump($obj);

// echo $obj->getResult();

問題就在 $obj->setNum(2,2); 這里，但是怎么看流程，都好像沒什么問題的

回答

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全部回復 (3)

大家講道理2017-04-11 09:55:493樓

$obj = OperFactory::createrOper('+');這個OperFactory的createOper方法沒有返回值，應該return self::$obj = new OperAdd()

回復

迷茫2017-04-11 09:55:492樓

public static function createrOper($type){

try {

switch ($type){

case'+';

self::$obj = new OperAdd();

break;

case'-';

self::$obj = new OperSub();

break;

case'*';

self::$obj = new OperMul();

break;

case '/':

self::$obj = new Operp();

break;

default:

throw new Exception('unknow type');

}

} catch (Exception $e) {

echo $e->getMessage();

}

return self::$obj;

}

回復

巴扎黑2017-04-11 09:55:491樓

建議去翻譯下設計模式的資料設計模式，希望對你有幫助

回復

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