我不确定是不是因为我没有睡觉，或者因为我以前从未遇到过，但我不知道这个错误意味着什么。我正在尝试编译一个使用自定义对象与双向链表进行交互的程序，编译器一直告诉我以下内容：
19 errors found:
File: Z:\CS121\Project 6\prog6.java [line: 127]
Error: Z:\CS121\Project 6\prog6.java:127: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 130]
Error: Z:\CS121\Project 6\prog6.java:130: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 134]
Error: Z:\CS121\Project 6\prog6.java:134: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 136]
Error: Z:\CS121\Project 6\prog6.java:136: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 138]
Error: Z:\CS121\Project 6\prog6.java:138: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 140]
Error: Z:\CS121\Project 6\prog6.java:140: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 143]
Error: Z:\CS121\Project 6\prog6.java:143: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 144]
Error: Z:\CS121\Project 6\prog6.java:144: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 145]
Error: Z:\CS121\Project 6\prog6.java:145: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 146]
Error: Z:\CS121\Project 6\prog6.java:146: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 149]
Error: Z:\CS121\Project 6\prog6.java:149: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 151]
Error: Z:\CS121\Project 6\prog6.java:151: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 156]
Error: Z:\CS121\Project 6\prog6.java:156: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 158]
Error: Z:\CS121\Project 6\prog6.java:158: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 160]
Error: Z:\CS121\Project 6\prog6.java:160: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 161]
Error: Z:\CS121\Project 6\prog6.java:161: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 165]
Error: Z:\CS121\Project 6\prog6.java:165: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 166]
Error: Z:\CS121\Project 6\prog6.java:166: class, interface, or enum expected
File: Z:\CS121\Project 6\prog6.java [line: 169]
Error: Z:\CS121\Project 6\prog6.java:169: class, interface, or enum expected
这是我的代码：
import java.util.LinkedList;
import java.util.ListIterator;
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
class prog6 {
public static void main(String args[]) throws FileNotFoundException
{
Scanner kb=new Scanner(System.in);
String tempName, keyName;
Product tempProduct, temp;
double tempPrice;
boolean found;
/* Here, add code to delcare and/or create a linked list
and, if necessary, an iterator.
*/
LinkedList<Product> list = new LinkedList<Product>();
ListIterator<Product> iter = list.listIterator();
//the following code reads product data from the file data.txt
//and saves the product data in the linked list
Scanner infile=new Scanner(new File("data.txt"));
while(infile.hasNextLine())
{
tempProduct=tempProduct.addFirst(infile.nextLine(), infile.nextDouble());
infile.nextLine(); //skip end-of-line
/*here, add code to add the object tempProduct
to the beginning of the linked list*/
}
infile.close();
while(true)
{
System.out.println();
System.out.println();
//show prompt messages and menu
System.out.println("Please select one of the follwing actions:");
System.out.println("q - Quit");
System.out.println("a - print the product list");
System.out.println("b - add a product");
System.out.println("c - enter a product name to find the product record");
System.out.println("d - delete a product");
System.out.println("Please enter q, a, b, c, or d:");
String selection=kb.nextLine(); //read user's selection
if (selection.equals("")) continue; //if selection is "", show menu again
switch (selection.charAt(0))
{
case 'q':
System.out.println("Thank you");
return;
/*write code for the cases 'a','b','c' and 'd' */
case 'a':
temp = list;
while (temp != null)
{
System.out.println (temp.data);
temp = temp.next;
}
System.out.println();
break;
case 'b':
System.out.println("Please enter the name of the new product:");
tempName = kb.nextLine();
System.out.println("Please enter the price of the new product:");
tempPrice = kb.nextDouble();
temp = new node(tempName, tempPrice);
temp.next = list;
list = temp;
break;
case 'c':
System.out.println("Please enter a product name:");
n=kb.nextLine();
tempProduct = list.search(n);
if(tempProduct == null)
System.out.println("Cannot find product named " + n);
else
System.out.println("Product found: " + tempProduct);
break;
case 'd':
System.out.println("Please enter name of a customer to remove from list:");
tempString = kb.nextLine();
list = delete(list, tempString);
break;
default: System.out.println("Incorrect selection.\n");
} //end switch
} //end while
} //end main();
} //end class prog6
class Product
{
String name;
double price;
public Product(String n, double p)
{ name=n;
price=p;
} //end Constructor
public String toString()
{
return String.format("%-20s%10.2f", name, price);
}
} //end class Product
public Product search (String key)
{
node temp = head;
while (temp != null)
{
if (temp.data.name.equals(key))
return temp.data;
else
temp = temp.next;
}
return null;
}
public void add (Product a)
{
node temp = new node (a);
temp.next = head;
head = temp;
}
public Boolean delete (String namekey, Product a)
{
node previous = null;
node current = head;
while (current != null)
{
if (current.name.equals(namekey))
{
current = current.next;
if (previous == null)
previous = current;
else
previous.next = current;
return true;
}//end if
else
{
previous = current;
current = current.next;
}//end else
}//end while
return false;
}
非常感谢任何帮助！
答案 0 :(得分：1)
错误在行
public Product search (String key)
原因是java只接受顶层的类，接口或枚举定义（因为消息非常明确地说明了这一点）。
答案 1 :(得分：1)
方法：
public Product search (String key)
是在课堂外定义的。