如果有以下需求,你是一個貨棧的倉庫保管員,貨棧進口以下多種水果,目前主要是蘋果,香蕉和桔子,貨棧不但需要記錄每批次的品種,單價,還要得出每種水果的總個數,總錢數. 請問該如何編制程序.
記錄每批次不難,一個批次鏈表就可以解決問題,有點意思的部分在于得出每種水果的總個數,總錢數,如果說在加入批次信息時進行處理,根據類型分別判斷,用六個量(分別針對每種水果的總個數,總錢數)分別進行統計.這種方法容易使程序固化,如果增加一個水果品種的話會導致增加兩個變量,所以說這里統計信息需要動態起來,用List或Hashtable是個不錯的選擇,相對而言Hashtable在種類較多時更好.
具體來說做法是用一個Hashtable存儲統計信息,Hashtable的鍵為水果類型,Hashtable的值為統計信息;每當有新批次水果到達時,查看Hashtable中是否有這種類型的統計信息,有則取出信息,在原基礎上加上新值,否則加入一個新統計信息.
代碼如下:
package com.sitinspring;
/**
* 水果基類
*
* @author: sitinspring(junglesong@gmail.com)
* @date: 2007-11-25
*/
public class Fruit {
// 水果批次類型
protected String type;
// 水果批次數量
protected int count;
// 單價
protected double unitPrice;
public Fruit(int count, double unitPrice) {
this.count = count;
this.unitPrice = unitPrice;
}
public int getCount() {
return count;
}
public String getType() {
return type;
}
public double getUnitPrice() {
return unitPrice;
}
public String toString() {
return "類型=" + type + " 數量=" + count + " 單價=" + unitPrice + " 合計="
+ count * unitPrice + "\r\n";
}
}
package com.sitinspring;
/**
* 蘋果類
*
* @author: sitinspring(junglesong@gmail.com)
* @date: 2007-11-25
*/
public class Apple extends Fruit {
public Apple(int count, double unitPrice) {
super(count, unitPrice);
this.type = "Apple";
}
}
package com.sitinspring;
/**
* 香蕉類
*
* @author: sitinspring(junglesong@gmail.com)
* @date: 2007-11-25
*/
public class Banana extends Fruit {
public Banana(int count, double unitPrice) {
super(count, unitPrice);
this.type = "Banana";
}
}
package com.sitinspring;
/**
* 桔子類
* @author: sitinspring(junglesong@gmail.com)
* @date: 2007-11-25
*/
public class Orange extends Fruit{
public Orange(int count,double unitPrice){
super(count,unitPrice);
this.type="Orange";
}
}
package com.sitinspring;
/**
* 水果統計信息類
*
* @author: sitinspring(junglesong@gmail.com)
* @date: 2007-11-25
*/
public class FruitSumary {
// 類型
protected String type;
// 總數
protected int count;
// 總價
protected double price;
public FruitSumary(String type, int count, double unitPrice) {
this.type = type;
this.count = count;
this.price = unitPrice;
}
public String toString() {
return "類型=" + type + " 總數量=" + count + " 總合計=" + price + "\r\n";
}
public int getCount() {
return count;
}
public void setCount(int count) {
this.count = count;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
}
package com.sitinspring;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
/**
* 貨棧進貨記錄
*
* @author: sitinspring(junglesong@gmail.com)
* @date: 2007-11-25
*/
public class StockHouseMemo {
// 水果批次記錄
private List<Fruit> fruits;
// 統計信息
private Hashtable<String,FruitSumary> fruitSumaries;
/**
* 添加水果批次記錄
*
* @param fruit
*/
public void addFruit(Fruit fruit) {
// 添加批次記錄
if (fruits == null) {
fruits = new ArrayList<Fruit>();
}
fruits.add(fruit);
// 添加統計記錄
if (fruitSumaries == null) {
fruitSumaries = new Hashtable<String,FruitSumary>();
}
String fruitType=fruit.getType();
// 取出同類型的統計信息
FruitSumary sumaryFound = findSummaryByType(fruitType);
if (sumaryFound != null) {
// 有記錄
sumaryFound.setCount(sumaryFound.getCount()
+ fruit.getCount());
sumaryFound.setPrice(sumaryFound.getPrice()
+ fruit.getUnitPrice() * fruit.getCount());
} else {
// 無記錄
fruitSumaries.put(fruitType,new FruitSumary(fruit.getType(),
fruit.getCount(), fruit.getUnitPrice() * fruit.getCount()));
}
}
/**
* 取得和fruitInput類型對應的統計信息記錄
*
* @param fruitInput
* @return
*/
private FruitSumary findSummaryByType(String fruitType) {
if(fruitSumaries.containsKey(fruitType)){
return fruitSumaries.get(fruitType);
}
return null;
}
/**
* 取得水果進貨詳細信息
*
* @return
*/
public String getDetailFruitInfo() {
String retval = "----------水果進貨詳細信息-----------\r\n";
for (Fruit fruit : fruits) {
retval += fruit; // 等于fruit.toString()
}
retval += "----------------------------------------";
return retval;
}
/**
* 取得水果進貨統計信息
*
* @return
*/
public String getSummaryFruitInfo() {
String retval = "----------水果進貨統計信息-----------\r\n";
for (FruitSumary fruitSumary : fruitSumaries.values()) {
retval += fruitSumary; // 等于fruitSumary.toString()
}
retval += "----------------------------------------";
return retval;
}
public void writeToFile(String fileName) {
try {
BufferedWriter out = new BufferedWriter(new FileWriter(fileName));
String outputText = getDetailFruitInfo()+"\r\n";
outputText += getSummaryFruitInfo();
out.write(outputText);
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
package com.sitinspring;
/**
* 程序入口
* @author: sitinspring(junglesong@gmail.com)
* @date: 2007-11-25
*/
public class Main{
public static void main(String[] args){
StockHouseMemo stackHouseMemo=new StockHouseMemo();
stackHouseMemo.addFruit(new Apple(10,0.5));
stackHouseMemo.addFruit(new Apple(12,1.5));
stackHouseMemo.addFruit(new Banana(13,2.5));
stackHouseMemo.addFruit(new Banana(14,3.5));
stackHouseMemo.addFruit(new Banana(15,4.5));
stackHouseMemo.addFruit(new Orange(16,5.5));
stackHouseMemo.addFruit(new Orange(17,6.5));
System.out.println(stackHouseMemo.getDetailFruitInfo());
System.out.println(stackHouseMemo.getSummaryFruitInfo());
stackHouseMemo.writeToFile("輸出信息.txt");
}
}
輸出為:
----------水果進貨詳細信息-----------
類型=Apple 數量=10 單價=0.5 合計=5.0
類型=Apple 數量=12 單價=1.5 合計=18.0
類型=Banana 數量=13 單價=2.5 合計=32.5
類型=Banana 數量=14 單價=3.5 合計=49.0
類型=Banana 數量=15 單價=4.5 合計=67.5
類型=Orange 數量=16 單價=5.5 合計=88.0
類型=Orange 數量=17 單價=6.5 合計=110.5
----------------------------------------
----------水果進貨統計信息-----------
類型=Orange 總數量=33 總合計=198.5
類型=Apple 總數量=22 總合計=23.0
類型=Banana 總數量=42 總合計=149.0
----------------------------------------
代碼下載:
http://m.tkk7.com/Files/sitinspring/StockHouseManager20071125101919.rar