Question

import acm.program.*; 
import acm.util.*;

public class Order { 
public  int ocode;       
public String cname ;  
public String cphone ;  
public double price ; 
public double discount ; 
public int delay;
double finalprice  ;

public Order (int ocode, Item aItems, String cname, String cphone, String odate) {

     this.cname= cname;
     this.cphone= cphone;
     this.odate= odate;
     this.ocode = ocode; 
     price = aItems.getPrice() ; 
     if (aItems instanceof Peripherals){
          discount = price*0.25 ; 
     } 
     else if (aItems instanceof Hardware){
           discount = price * 0.3 ; 
     }  
     finalprice = price - discount ; 
     delay = rgen.nextInt(1,40) ;

  } 
  RandomGenerator rgen= RandomGenerator.getInstance() ;   

 public Item getItem() {
 return aItems;
 }

 public String getCname() {
  return cname;
}

public String  getCphone () {
return cphone;
}

public String getOdate () {
 return odate;
}


  public void print() {
         if(aItems instanceof Monitor){

              println( "Order Number: " + "( " +  ocode + " )" + " ,Ordered      Monitor: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " and your order will delay "  +delay + " days" );              
           }            
          if(aItems instanceof Mouse){

              println( "Order Number: " + "( " +  ocode + " )" + " ,Ordered Mouse: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " " + delay  );
           }
          if(aItems instanceof Printer){

              println( "Order Number: " + "( " +  ocode + " )" + " ,Ordered Printer: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " " + delay  );
           }
          if(aItems instanceof Keyboard){

              println( "Order Number: " + "( " +  ocode + " )" + " ,Ordered Keyboard: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " " + delay  );
           }
         if(aItems instanceof Proccesor){

              println( "Order Number: " + "( " +  ocode + " )" + " ,Ordered Processor: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " " + delay  );
           }

         if(aItems instanceof Motherboard){

              println( "Order Number: " + "( " +  ocode + " )" + " ,Ordered Motherboard: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " " + delay );
           }

         if(aItems instanceof Ram){

              println( "Order Number: " + "( " +  ocode + " )" + " ,Ordered Ram Memory: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " " + delay  );
           }
        if(aItems instanceof Gcard){

              println( "Order Number: " + "( " +  ocode + " )" + " ,Ordered Graphics card: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " " + delay  );
           }

         if(aItems instanceof HardDrive){

              println( "Order Number: " + "( " +  ocode + " )" + " ,Ordered HardDrive: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " " + delay  );
           }


    }
 }

当我尝试编译它时，它给了我这些错误：

Order.java:54: error: cannot find symbol
                  println( "Order Number: " + "( " +  ocode + " )" + " ,Orde
red Monitor: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's nam
e: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + "
and your order will delay "  +delay + " days" );
                  ^
symbol:   method println(String)
location: class Order
Order.java:58: error: cannot find symbol
                  println( "Order Number: " + "( " +  ocode + " )" + " ,Orde
red Mouse: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's name:
  " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + " "
+ delay  );
                  ^
symbol:   method println(String)
location: class Order
Order.java:62: error: cannot find symbol
                  println( "Order Number: " + "( " +  ocode + " )" + " ,Orde
red Printer: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's nam
e: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + "
" + delay  );
                  ^
symbol:   method println(String)
location: class Order
Order.java:66: error: cannot find symbol
                  println( "Order Number: " + "( " +  ocode + " )" + " ,Orde
red Keyboard: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's na
me: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate + "
" + delay  );
                  ^
symbol:   method println(String)
location: class Order
Order.java:70: error: cannot find symbol
                  println( "Order Number: " + "( " +  ocode + " )" + " ,Orde
red Processor: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's n
ame: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate +
" " + delay  );
                  ^
symbol:   method println(String)
location: class Order
Order.java:75: error: cannot find symbol
                  println( "Order Number: " + "( " +  ocode + " )" + " ,Orde
red Motherboard: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's
 name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate
+ " " + delay );
                  ^
symbol:   method println(String)
location: class Order
Order.java:80: error: cannot find symbol
                  println( "Order Number: " + "( " +  ocode + " )" + " ,Orde
red Ram Memory: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's
name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate +
" " + delay  );
                  ^
symbol:   method println(String)
location: class Order
Order.java:84: error: cannot find symbol
                  println( "Order Number: " + "( " +  ocode + " )" + " ,Orde
red Graphics card: " +   aItems   + " ,Final price: " + finalprice + " ,Customer
's name: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odat
 e + " " + delay  );
                  ^
  symbol:   method println(String)
 location: class Order
 Order.java:89: error: cannot find symbol
                  println( "Order Number: " + "( " +  ocode + " )" + " ,Orde
red HardDrive: " +   aItems   + " ,Final price: " + finalprice + " ,Customer's n
ame: " + cname + " ,Customers phone: " + cphone + " ,Date of order: " + odate +
" " + delay  );
                  ^
symbol:   method println(String)
location: class Order
9 errors

那是什么？ javac不明白这些是字符串吗？如果现在，为什么？请帮我编译这个东西。类主要由主类调用，它创建了表示在线商店订单的类顺序对象。

Answer 1

尝试使用System.out.println（）而不是println（）

Answer 2

如果acm，方法println是IOModel接口的一部分。因此，除非您的类实现此接口，否则您无法使用它 - 您只是尝试从继承自Object的类中调用它。显然，Object类本身没有这样的方法。但是，如果您将Order类放在继承自acm.program.Program或acm.program.ConsoleProgram的某个类中，则可以使用它。

Answer 3

我会像这样写

System.out.println( "Order Number: " + "( " +  ocode + " )" 
                + " ,Ordered      " + aItems.getClass().getSimpleName() 
                + ": " +   aItems   
                + " ,Final price: " + finalprice 
                + " ,Customer's name: " + cname 
                + " ,Customers phone: " + cphone 
                + " ,Date of order: " + odate 
                + " and your order will delay "  +delay + " days" );

这样可以节省每种类型物品的println。

Javac无法识别字符串

3 个答案: