我很新Java
,我正在使用BlueJ
. 我不断收到错误:
method find in class Catalog cannot be applied to given types;
required: int
found: Item
reason: actual argument Item cannot be converted to int by method invocation conversion
我很困惑,反过来不知道如何解决这个问题。希望有人可以帮助我。先感谢您。
这是我的 Program2 课程:
import java.util.*;
public class Program2 {
public static void main(String[] args) {
Scanner kbd = new Scanner(System.in);
Catalog store = new Catalog(3);
int itemnum;
Item item;
try {
store.insert
(new Music(1111, "Gold", 12.00, "Abba"));
store.insert
(new Movie(2222, "Mamma Mia", 16.00, "Meryl Streep"));
store.insert
(new Book(3333, "DaVinci Code", 8.00, "Dan Brown"));
store.insert
(new Music(4444, "Legend", 15.00, "Bob Marley"));
} catch (CatalogFull exc) {
System.out.println(exc);
}
// Insert code here to perform a sequence of
// interactive transactions with the user.
// The user enters an item number and the program
// either displays the item or prints an error message
// if the item is not found. The program terminates
// when the user enters zero as the item number.
while (!item.equals("0")) {
itemnum = store.find(item); //Getting error on ".find"
if (itemnum != null) {
System.out.print(itemnum);
} else {
System.out.printf("%s was not found.%n", item);
}
System.out.println();
System.out.print("Player (0 to exit)? ");
item = kbd.next();
}
}
}
作为参考,这里class Catalog
也是:
public class Catalog {
private Item[] list;
private int size;
// Construct an empty catalog with the specified capacity.
public Catalog(int max) {
list = new Item[max];
size = 0;
}
// Insert a new item into the catalog.
// Throw a CatalogFull exception if the catalog is full.
public void insert(Item obj) throws CatalogFull {
if (list.length == size) {
throw new CatalogFull();
}
list[size] = obj;
++size;
}
// Search the catalog for the item whose item number
// is the parameter id. Return the matching object
// if the search succeeds. Throw an ItemNotFound
// exception if the search fails.
public Item find(int id) throws ItemNotFound {
for (int pos = 0; pos < size; ++pos){
if (id == list[pos].getItemNumber()){
return list[pos];
}
}
throw new ItemNotFound(id);
}
}