我有一個任務,我必須創建三個類,一個執行所有I/O的客戶端類,一個維護catalogItem對象列表的catalog類和一個定義單個項目的catalogItem類商店的目錄。一個java數組對象
我試着從一開始就簡單地開始創建數組,並確保它在接受數據之前,我轉到其餘任務。我能夠毫無問題地編譯它,但是當我嘗試顯示數組時,我什麼都沒有。
import java.util.Scanner;
public class lab3
{
public static void main(String args[])
{
Scanner in = new Scanner(System.in);
Catalog catalog = new Catalog();
boolean endCatalog = false;
while (!endCatalog)
{
System.out.println("Please choose and option: \n"
+ "1 - Display all items of the catalog\n"
+ "2 - Display an item by keyword\n"
+ "3 - Add an item to the catalog\n"
+ "4 - Remove an item from the catalog\n"
+ "5 - Change the cost of one item in the catalog\n"
+ "6 - Change the cost of all items in catalog by percent\n"
+ "7 - Exit");
int choice = in.nextInt();
switch (choice) {
case 1: System.out.println(catalog.displayAll()); break;
case 2: System.out.println("Display keyword"); break;
case 3: System.out.println("Add item:\nEnter ID: ");
int newId=in.nextInt();
System.out.println("Enter description: ");
String newDesc=in.next();
System.out.println("Enter cost: ");
double newCost=in.nextDouble();
catalog.add(newId, newDesc, newCost); break;
case 4: System.out.println("Remove item"); break;
case 5: System.out.println("Change cost of one item"); break;
case 6: System.out.println("Change cost by %"); break;
case 7: endCatalog=true; break; }
}
}
}
class Catalog
{
final static int MAX = 100;
private CatalogItem[] catalogItems;
int inUse;
public Catalog()
{
catalogItems=new CatalogItem[MAX];
}
public void add(CatalogItem newItem)
{
inUse = 0;
if(inUse<MAX) {
catalogItems[inUse] = newItem;
inUse++; }
}
public void add(int newId, String newDesc, double newCost)
{
CatalogItem newItem = new CatalogItem(newId, newDesc, newCost);
}
/*public void remove(int id)
{
}
public String find(String keyword)
{
}
public void changeCost(int id, double percent)
{
}
public void increaseCost(double percent)
{
}
public String toString()
{
}
public boolean equals(Catalog obj)
{
}*/
public String displayAll()
{
String str = "";
for (int i=0; i<inUse; i++) {
str = str + "\n" + catalogItems[i]; }
return str;
}
}
class CatalogItem
{
private int itemID;
private String description;
private double cost;
public CatalogItem()
{
itemID = 1;
description = " ";
cost = 0.0;
}
public CatalogItem(int newID, String newDesc, double newCost)
{
itemID = newID;
description = newDesc;
cost = newCost;
}
public int getItemID()
{
return itemID;
}
public void setItemID(int newID)
{
itemID=newID;
}
public String getDescription()
{
return description;
}
public void setDescription(String newDesc)
{
description=newDesc;
}
public double getCost()
{
return cost;
}
public void setCost(double newCost)
{
cost=newCost;
}
public String toString()
{
return itemID + ", " + description + ", " + cost;
}
public boolean equals(CatalogItem obj)
{
return false;
}
}
您是否添加項目? – m0skit0 2012-02-26 19:37:41