设计模式 工厂模式

采用封装方式

<?php
    class Calc{
        /**
         * 计算结果
         *
         * @param int|float $num1
         * @param int|float $num2
         * @param string $operator
         * @return int|float
         */
        public function calculate($num1,$num2,$operator){
            try {
                $result=0;
                switch ($operator){
                    case '+':
                        $result= $num1+$num2;
                        break;
                    case '-':
                        $result= $num1-$num2;
                        break;
                    case '*':
                        $result= $num1*$num2;
                        break;
                    case '/':
                        if ($num2==0) {
                            throw new Exception("除数不能为0");
                        }
                        $result= $num1/$num2;
                        break;
                }
            return $result;
            }catch (Exception $e){
                echo "您输入有误:".$e->getMessage();
            }
        }
    }
    $test=new Calc();
//    echo $test->calculate(2,3,'+');//打印:5
    echo $test->calculate(5,0,'/');//打印:您输入有误:除数不能为0
?>