Java206 四則運算

package java實用級;

public class J206 {

    public J206() {

        // TODO Auto-generated constructor stub

    }

    public static void main(String args[]){

       

        try{

            if(args.length==3){

                double a = Double.valueOf(args[0]);

                double b = Double.valueOf(args[2]);

                     if(args[1].equals("+")){System.out.println(args[0]+args[1]+args[2]+"="+(a+b));}

                     else if(args[1].equals("-")){System.out.println(args[0]+args[1]+args[2]+"="+(a-b));}

                     else if(args[1].equals("*")){System.out.println(args[0]+args[1]+args[2]+"="+(a*b));}

                     else if(args[1].equals("/")){

                            if(b==0){System.out.println("除數不能為零"); }

                            else{System.out.println(args[0]+args[1]+args[2]+"="+(a/b));}                                                          

                     }

                     else{System.out.println("運算子錯誤");}

            }  

            else{System.out.println("引數數目不對");}                                           

        }

        catch(Exception e)

        {

            System.out.println("引數格式不對,請使用如下格式");

            System.out.println("Calc 1 + 2");

        }

    }

}