该程序应该模仿杂货店的购物。它几乎完成，但我需要实现二进制搜索。它应该在数组购物车中搜索该人正在寻找的字符串。但是，它不起作用，我不知道如何解决它。如果你能弄清楚我需要如何修复它，我将不胜感激。我知道问题不在Item中。我得到的错误是ShoppingCart无法解析为变量
// **********************************************************************
// ShoppingCart.java
//
// Represents a shopping cart as an array of items
// **********************************************************************
import java.util.*;
import java.text.NumberFormat;
public class ShoppingCart
{
Scanner scan = new Scanner(System.in);
private int itemCount; // total number of items in the cart
private double totalPrice; // total price of items in the cart
private int capacity; // current cart capacity
Item[] cart;
int i = 0;
// -----------------------------------------------------------
// Creates an empty shopping cart with a capacity of 5 items.
// -----------------------------------------------------------
public ShoppingCart()
{
capacity = 5;
itemCount = 0;
totalPrice = 0.0;
cart = new Item[capacity];
}
// -------------------------------------------------------
// Adds an item to the shopping cart.
// -------------------------------------------------------
public void addToCart(String itemName, double price, int quantity)
{
if(i == cart.length)
{
increaseSize();
}
else
{
Item newItem = new Item(itemName, price, quantity);
cart[i] = newItem;
totalPrice = (price*quantity)+totalPrice;
itemCount++;
i++;
}
}
// -------------------------------------------------------
// Returns the contents of the cart together with
// summary information.
// -------------------------------------------------------
public String toString()
{
NumberFormat fmt = NumberFormat.getCurrencyInstance();
String contents = "\nShopping Cart\n";
contents += "\nItem:\t\tUnit Price: \tQuantity:\t\tTotal:\n";
for(int i = 0; i < itemCount; i++)
contents += cart[i].toString() + "\n";
contents += "\nTotal Price: " + fmt.format(totalPrice);
contents += "\n";
return contents;
}
// ---------------------------------------------------------
// Increases the capacity of the shopping cart by 3
// ---------------------------------------------------------
private void increaseSize()
{
Item[] temp = new Item[cart.length+3];
for(int item=0; item < cart.length; item++)
{
temp[item] = cart[item];
}
cart = temp;
}
public void binarySearch(ShoppingCart sc)
{
System.out.println("Type in the object you would like to search for: ");
String object = scan.next();
int high = cart.length-1;
int low = 0;
int middle = (low+high)/2;
while(!(cart[middle].getName().equals(object)) && low<=high)
{
if((cart[middle].getName()).compareTo(object) > 0)
if(cart[middle].getName().equals(object))
high = middle-1;
else
low = middle+1;
middle = (low+high)/2;
}
if(cart[middle].getName().equals(object))
System.out.println("Your item is found!");
else
System.out.println("Your item is not found.");
}
}
import java.util.*;
public class Shop
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
String userAns,name;
int amount;
double price;
ShoppingCart newCart = new ShoppingCart();
System.out.println("Would you like to shop at the store?");
userAns = scan.nextLine();
if(userAns.equalsIgnoreCase("yes"))
{
while(userAns.equalsIgnoreCase("yes"))
{
System.out.println("What are the item names?");
name = scan.next();
System.out.println("How many would you like to buy?");
amount = scan.nextInt();
System.out.println("How much is it?");
price = scan.nextDouble();
newCart.addToCart(name,price,amount);
System.out.println(newCart);
System.out.println("Would you like to continue shopping at the store?");
userAns = scan.next();
}
System.out.println("Would you like to check your cart for an item?");
String userScan = scan.next();
if(userScan.equalsIgnoreCase("yes"))
binarySearch(newCart);
}
else
System.out.println("Have a nice day!");
}
}
// ***************************************************************
// Item.java
//
// Represents an item in a shopping cart.
// ***************************************************************
import java.text.NumberFormat;
public class Item
{
private String name;
private double price;
private int quantity;
// -------------------------------------------------------
// Create a new item with the given attributes.
// -------------------------------------------------------
public Item (String itemName, double itemPrice, int numPurchased)
{
name = itemName;
price = itemPrice;
quantity = numPurchased;
}
// -------------------------------------------------------
// Return a string with the information about the item
// -------------------------------------------------------
public String toString()
{
NumberFormat fmt = NumberFormat.getCurrencyInstance();
return (name + "\t\t" + fmt.format(price) + "\t\t" + quantity + "\t\t"
+ fmt.format(price*quantity));
}
// -------------------------------------------------
// Returns the unit price of the item
// -------------------------------------------------
public double getPrice()
{
return price;
}
// -------------------------------------------------
// Returns the name of the item
// -------------------------------------------------
public String getName()
{
return name;
}
// -------------------------------------------------
// Returns the quantity of the item
// -------------------------------------------------
public int getQuantity()
{
return quantity;
}
}
答案 0 :(得分：0)
当您调用binarySearch(...)方法时，您将类名，ShoppingCart传递给方法参数，这对我或编译器没有意义。相反，你应该传递ShoppingCart变量newCart，这更有意义。
更改
binarySearch(ShoppingCart); // you're passing in a class here, not the object
为：
binarySearch(newCart); // here you pass in the ShoppingCart object declared earlier
修改
您的binarySearch方法被误解了。它是ShoppingCart类的一种方法，因此不应该将ShoppingCart对象传递给它，而应该在ShoppingCart对象上调用 。相反，你应该传入要搜索的对象。
总而言之：
newCart.binarySearch(someItem);