oop第二次作业
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一.前言
第四次作业
涉及知识点
考察
1.降低时间复杂度，使代码效率更高
例如quickSort方法的熟练运用，以及HashSet的使用
点击查看代码
//quickSort的一个示例
public static void quickSort(int[] a,int begin,int end)
int i = begin;
int j = end;
int t, temp;
if(i >= j)
return;
temp = a[i];
while(i != j)
while(a[j] >= temp && i < j)
j--;
while(a[i] <= temp && i < j)
i++;
if(i < j)
t = a[j];
a[j] =a [i];
a[i] = t;
a[begin] = a[i];
a[i] = temp;
quickSort(a, begin, i-1);
quickSort(a, i+1, end);
2.LocalDate类的使用
(1)日期转换
点击查看代码
LocalDate localDate = LocalDate.parse("2018-02-18");
String formattedDate = localDate.format(DateTimeFormatter.ofPattern("MMM dd, yyyy"));
(2)比较两个日期大小(返回值为true或false)
isAfter(ChronoLocalDate other): 检查此日期是否在给定日期之后。
isBefore(ChronoLocalDate other): 检查此日期是否在给定日期之前。
isEqual(ChronoLocalDate other): 检查此日期是否等于给定日期。
(3)计算两个日期间的时间量
点击查看代码
LocalDate localDate = LocalDate.parse("2018-02-18");
Period period = localDate.until(LocalDate.parse("2018-03-28"));
System.out.println(period.getDays());
long val = localDate.until(LocalDate.parse("2018-03-28"), ChronoUnit.DAYS);
3.使得代码具有封装性
4.其他：
忽略大小写排序
Arrays.sort(str, String.CASE_INSENSITIVE_ORDER)
题量和难度
题量中等，除第一题外，其他题目难度中等。
第五次作业
涉及知识点
考察
正则表达式的基本使用
(1)用正则表达式表示一定范围内的数字，如取值范围为[1,1000)的数字。
（[1-9][0-9][0-9][0-9])
含义：首位数字为1-9，第二位为0-9...
(2)([0-9]3[a-zA-Z]）
含义：前3个数为0-9的数字，第四个为不区分大小写的字母
(3)^2020(1[1-7]|7[1-3]|8[1-2]|61)(0[1-9]|[1-4][0-9])
含义：以2020开头，5、6两个数为1117或7173或81、82或61...
题量和难度
题量中等，题目比较简单
第六次作业
涉及知识点
考察
设计，对类的设计，有哪些类；逻辑，if-else语句较多，需要准确判定条件的符合程度。
二.设计与分析
题目集4
7-1
题目分析
题目给出的信息包括三部分：菜谱，订单(桌号、点菜记录、代点菜记录、删除点菜记录)，结束。
根据三部分的信息，截取每一条信息的长度，通过长度判断该信息属于哪一类。
输入：
菜谱包括：菜名、单价
订单：桌号包括：桌号、时间
点菜记录包括：序号、菜名、份额、份数
代点菜记录包括：被点菜的桌号、序号、菜名、份额、份数
删除点菜记录包括：delete和点菜序号
过程：
信息长度为2：(1)菜谱(读入菜谱）
(2)删除点菜记录(删除记录有效，打标记，算总价时不计入；删除记录无效，输出delete error）
信息长度为4：(1)桌号及时间(记录桌号和时间),输出桌号
(2)点菜记录(菜名存在，输出序号+菜名+单价；菜名不存在，输出菜名+does not exist）
信息长度为5：代点菜记录(代点桌号存在，输出相关信息)
输出：
(1)输出桌号
(2)输出菜单(判断菜名是否存在)
(3)代点菜记录
(4)删除点菜记录
(5)重复以上记录，直到最后一个桌号结束
(6)输出桌号对应的信息，如果在营业时间内，输出桌号+总价；如果不在营业时间，输出桌号+out of opening hours
源码分析
类图
源码
代码是别人的，我自己没写出来
点击查看代码
import java.time.LocalDateTime;
import java.util.*;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
Menu menu = new Menu();
Table[] tables = new Table[10];
int dishAmount = 0;//菜单菜的数目
int orderAmount = 0;//点菜记录的数目（包括带点菜的记录）
Dish dish;
int tableAmount = 0;//桌子的数目
int count;//数组长度
String[] temp;//输入字符串去除空格后的数组
int a1,a2,a3,a4,a5;
while (true)
String string = input.nextLine();
temp = string.split(" ");
if(string.equals("end"))
break;
count = temp.length;
if (count == 2)
if (temp[1].equals("delete"))
a1 = Integer.parseInt(temp[0]);
if (tables[tableAmount].order.delARecordByOrderNum(a1) == 0)
System.out.println("delete error;");
else
int c = tables[tableAmount].order.delARecordByOrderNum(a1);//要删除序号的点菜记录的价格
tables[tableAmount].order.sum -= c;//删除记录后那桌的未打折的总价格
else
a2 = Integer.parseInt(temp[1]);
menu.dishs[dishAmount] = menu.addDish(temp[0], a2);//添加新的菜到菜单里面
dishAmount++;//菜的数目加1
else if (count == 4)
if (temp[0].equals("table"))
tableAmount++;//桌子数加一
orderAmount = 0;//每个桌子的点菜记录数目不同，创建一个新的类时需要重置数目
tables[tableAmount] = new Table(temp[1], temp[2], temp[3]);//创建一个新的类
tables[tableAmount].processTime();//处理桌子的日期和时间
tables[tableAmount].setDiscount();//设置每个桌子时间对应的菜的折扣
System.out.println("table " + temp[1] + ": ");
else
a3 = Integer.parseInt(temp[0]);//序号
a4 = Integer.parseInt(temp[2]);//份额
a5 = Integer.parseInt(temp[3]);//份数
tables[tableAmount].order.addARecord(a3, temp[1],a4 , a5);//使用函数给点菜记录赋予相关的序号、菜名、份额、份数，将该条记录添加到总记录中
dish = menu.searthDish(temp[1]);//找点菜记录的菜名，存在菜名，返回dish,否则返回null
if(dish==null)
System.out.println(temp[1]+" does not exist");
if (dish != null)
tables[tableAmount].order.records[orderAmount].d = dish;//让记录的菜等于dish，以方便获得菜的价钱
int a = tables[tableAmount].order.records[orderAmount].getPrice();//计算记录的价格
System.out.println(tables[tableAmount].order.records[orderAmount].orderNum + " " + dish.name + " " + a);
tables[tableAmount].order.sum += a;//把该记录的价格加到该桌子的总价格中
orderAmount++;//点菜记录加一
else if (count == 5)
a1 = Integer.parseInt(temp[1]);//序号
a2 = Integer.parseInt(temp[3]);//份额
a3 = Integer.parseInt(temp[4]);//份数
tables[tableAmount].order.addARecord(a1, temp[2], a2, a3);//使用函数给代点菜记录赋予相关的序号、菜名、份额、份数，将该条记录添加到总记录中
dish = menu.searthDish(temp[2]);//找点菜记录的菜名，存在菜名，返回dish,否则返回null
if(dish==null)
System.out.println(temp[2]+" does not exist");
if (dish != null)
tables[tableAmount].order.records[orderAmount].d = dish;//让记录的菜等于dish，以方便获得菜的价钱
int b = tables[tableAmount].order.records[orderAmount].getPrice();////计算记录的价格
System.out.println(temp[1] + " table " + tables[tableAmount].tableNum + " pay for table " + temp[0] + " " + b);
tables[tableAmount].order.sum += b;//把该记录的价格加到该桌子的总价格中
orderAmount++;//点菜记录加一
for(int i = 1; i < tableAmount + 1; i++)
if(tables[i].getDiscount() > 0)
System.out.println("table " + tables[i].tableNum + ": "+Math.round(tables[i].order.getTotalPrice()*tables[i].getDiscount()));
else System.out.println("table " + tables[i].tableNum + " out of opening hours");
class Dish
String name;
int unit_price;
int getPrice(int portion)//计算菜品价格的方法，输入参数是点菜的份额（输入数据只能是1/2/3，代表小/中/大份）
if (portion == 0)
return 0;
else if (portion == 1)
return this.unit_price;
else if (portion == 2)
return (int)(this.unit_price * 1.5 + 0.5);
return this.unit_price * 2;
class Menu
Dish[] dishs = new Dish[10];
int dishCount = 0;
Dish searthDish(String dishName)
for(int i = dishCount-1; i >= 0; i--)
if(dishName.equals(dishs[i].name))
return dishs[i];
return null;
Dish addDish(String dishName, int unit_price)
Dish dish = new Dish();
dish.name = dishName;
dish.unit_price = unit_price;
dishCount ++;
return dish;
class Record
int orderNum;
Dish d = new Dish();
int num = 0;
int portion;
int getPrice()
return d.getPrice(portion) * num;
class Order
Record[] records = new Record[10];
int count = 0;
int sum;
void addARecord(int orderNum,String dishName,int portion,int num)
records[count] = new Record();
records[count].d.name = dishName;
records[count].orderNum = orderNum;
records[count].portion = portion;
records[count].num = num;
count++;
int getTotalPrice()
return sum;
int delARecordByOrderNum(int orderNum)
if(orderNum>count||orderNum<=0)
return 0;
else
return records[orderNum - 1].getPrice();
Record findRecordByNum(int orderNum)
for (int i = count - 1; i >= 0; i--)
if (orderNum == records[i].orderNum)
return records[i];
return null;
class Table
int tableNum;
String Date;
String tableTime;
int year;
int month;
int day;
int week;
int hh;
int mm;
int ss;
public Table()
public Table(String tableNum, String date, String tableTime)
this.tableNum = Integer.parseInt(tableNum);
Date = date;
this.tableTime = tableTime;
Order order = new Order();
float discount = -1;
void processTime()
String[] temp1 = Date.split("/");
String[] temp2 = tableTime.split("/");
year = Integer.parseInt(temp1[0]);
month = Integer.parseInt(temp1[1]);
day = Integer.parseInt(temp1[2]);
/*
Calendar date = Calendar.getInstance();
date.set(year, (month - 1), day);
week = date.get(Calendar.DAY_OF_WEEK);
if(week == 1)
week = 7;
else
week--;*/
//判断当前日期是第几周
LocalDateTime Date = LocalDateTime.of(year, month, day, hh, mm, ss);
week = Date.getDayOfWeek().getValue();//获得当前日期是第几周
hh = Integer.parseInt(temp2[0]);
mm = Integer.parseInt(temp2[1]);
ss = Integer.parseInt(temp2[2]);
void setDiscount()
if(week >= 1 && week <= 5)
if(hh >= 17 && hh < 20)
discount =0.8F;
else if(hh == 20 && mm < 30)
discount =0.8F;
else if(hh == 20 && mm == 30 && ss == 0)
discount =0.8F;
else if(hh >= 11 && hh <=13 || hh == 10 && mm >= 30)
discount =0.6F;
else if(hh == 14 && mm < 30)
discount =0.6F;
else if(hh == 14 && mm == 30 && ss == 0)
discount =0.6F;
else
if(hh >= 10 && hh <= 20)
discount = 1.0F;
else if(hh == 9&& mm >= 30)
discount = 1.0F;
else if(hh == 21 && mm < 30 || hh == 21 && mm == 30 && ss == 0)
discount = 1.0F;
float getDiscount()
return discount;
小结
需要先理清题目给的信息以及对信息的处理，要有整体思路，而不是上来就写，后面改起来会很要命。
题目集5
7-5
题目分析
这道题的基本功能实现和之前的大同小异，主要是把原来DateUtil里的属性Day,Month,Year单独拿出来做成了类，通过类之间的聚合关系实现功能，主要在于理清楚这些类之间的关系。
源码分析
类图
源码
点击查看代码
import java.util.Scanner;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
int year = 0;
int month = 0;
int day = 0;
int choice = input.nextInt();
if (choice == 1) // test getNextNDays method
int m = 0;
year = Integer.parseInt(input.next());
month = Integer.parseInt(input.next());
day = Integer.parseInt(input.next());
DateUtil date = new DateUtil(day, month, year);
if (!date.checkInputValidity())
System.out.println("Wrong Format");
System.exit(0);
m = input.nextInt();
if (m < 0)
System.out.println("Wrong Format");
System.exit(0);
System.out.println(date.getNextNDays(m).showDate());
else if (choice == 2) // test getPreviousNDays method
int n = 0;
year = Integer.parseInt(input.next());
month = Integer.parseInt(input.next());
day = Integer.parseInt(input.next());
DateUtil date = new DateUtil(day, month, year);
if (!date.checkInputValidity())
System.out.println("Wrong Format");
System.exit(0);
n = input.nextInt();
if (n < 0)
System.out.println("Wrong Format");
System.exit(0);
System.out.println(date.getPreviousNDays(n).showDate());
else if (choice == 3) //test getDaysofDates method
year = Integer.parseInt(input.next());
month = Integer.parseInt(input.next());
day = Integer.parseInt(input.next());
int anotherYear = Integer.parseInt(input.next());
int anotherMonth = Integer.parseInt(input.next());
int anotherDay = Integer.parseInt(input.next());
DateUtil fromDate = new DateUtil(day, month, year);
DateUtil toDate = new DateUtil(anotherDay, anotherMonth, anotherYear);
if (fromDate.checkInputValidity() && toDate.checkInputValidity())
System.out.println(fromDate.getDaysofDates(toDate));
else
System.out.println("Wrong Format");
System.exit(0);
else
System.out.println("Wrong Format");
System.exit(0);
class Day
private int value;
private Month month = new Month();//若写成private Month month;会导致NullPointerException错误
private int[] mon_maxnum = 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31;
Day()
Day(int yearValue, int monthValue, int dayValue)
month.getYear().setValue(yearValue);
month.setValue(monthValue);
this.value = dayValue;
public int getValue()
return value;
public void setValue(int value)
this.value = value;
public Month getMonth()
return month;
public void setMonth(Month value)
month.setValue(value.getValue());
month.getYear().setValue(value.getYear().getValue());
public void resetMin()
this.value = 1;
public void resetMax()
int temp = 0;
if (this.getMonth().getYear().isLeapYear() && this.getMonth().getValue() == 2)
temp = mon_maxnum[month.getValue() - 1] + 1;
if (this.getMonth().getValue() == 2)
if (this.getMonth().getYear().isLeapYear())
this.value = temp;
else
this.value = mon_maxnum[1];
else
this.value = mon_maxnum[month.getValue() - 1];
public boolean validate()
if (month.getYear().isLeapYear())
mon_maxnum[1]++;
if (this.value <= mon_maxnum[month.getValue() - 1] && this.value >= 1)
mon_maxnum[1] = 28;
return true;
mon_maxnum[1] = 28;
return false;
public void dayIncrement()
if (month.getYear().isLeapYear())
mon_maxnum[1]++;
if (this.value == mon_maxnum[this.getMonth().getValue() - 1])
this.month.monthIncrement();
resetMin();
else
this.value++;
mon_maxnum[1] = 28;
public void dayReduction()
if (this.value == 1)
this.month.monthReduction();
resetMax();
else
this.value--;
class Month
private int value = 0;
private Year year = new Year();
Month ()
Month (int yearValue, int monthValue)
year.setValue(yearValue);
this.value = monthValue;
public int getValue()
return value;
public void setValue(int value)
this.value = value;
public Year getYear()
return year;
public void setYear(Year year)
this.year = year;
public void resetMin()
this.value = 1;
public void resetMax()
this.value = 12;
public boolean validate()
if (this.value >= 1 && this.value <= 12)
return true;
return false;
public void monthIncrement()
if (this.value == 12)
this.year.yearIncrement();
resetMin();
else
this.value ++;
public void monthReduction()
if (this.value == 1)
this.year.yearReduction();
resetMax();
else
this.value --;
class Year
private int value = 0;
Year()
Year (int value)
this.value = value;
public int getValue ()
return this.value;
public void setValue (int value)
this.value = value;
public boolean isLeapYear ()
if ((this.value % 4 == 0 && this.value % 100 != 0) || this.value % 400 == 0)
return true;
return false;
public boolean validate ()
if (this.value >= 1900 && this.value <= 2050)
return true;
return false;
public void yearIncrement ()
this.value ++;
public void yearReduction ()
this.value --;
class DateUtil
private Day day = new Day();
DateUtil()
DateUtil(int d, int m, int y)
this.day.setValue(d);
this.day.getMonth().setValue(m);
this.day.getMonth().getYear().setValue(y);
public Day getDay()
return this.day;
public void setDay(Day d)
this.day.setValue(d.getValue());
this.day.getMonth().setValue(d.getMonth().getValue());
this.day.getMonth().getYear().setValue(d.getMonth().getYear().getValue());
public boolean checkInputValidity()
if (this.day.getMonth().getYear().validate() && this.day.getMonth().validate() && this.day.validate())
return true;
return false;
/*public boolean compareDates(DateUtil date)
if(this.day.getMonth().getYear().getValue() > date.getDay().getMonth().getYear().getValue())
return true;
if(this.day.getMonth().getYear().getValue() == date.getDay().getMonth().getYear().getValue() && this.day.getMonth().getValue() > date.getDay().getMonth().getValue())
return true;
if(this.day.getMonth().getYear().getValue() == date.getDay().getMonth().getYear().getValue() && this.day.getMonth().getValue() > date.getDay().getMonth().getValue() && this.day.getValue() > date.getDay().getValue())
return true;
return false;
*/
public boolean compareDates(DateUtil date)
if (this.day.getMonth().getYear().getValue() > date.getDay().getMonth().getYear().getValue())
return true;
if (this.day.getMonth().getValue() > date.getDay().getMonth().getValue())
return true;
if (this.day.getValue() > date.getDay().getValue())
return true;
return false;
public boolean equalTwoDates(DateUtil date)
if (this.day.getValue() == date.getDay().getValue() && this.day.getMonth().getValue() == date.getDay().getMonth().getValue() && this.day.getMonth().getYear().getValue() == date.getDay().getMonth().getYear().getValue())
return true;
return false;
public String showDate()
return (this.day.getMonth().getYear().getValue() + "-" + this.day.getMonth().getValue() + "-" + this.day.getValue());
public DateUtil getNextNDays(int n)
int i;
for (i = 0; i < n; i++)
this.day.dayIncrement();
return this;
public DateUtil getPreviousNDays(int n)
int i;
for (i = 0; i < n; i++)
this.day.dayReduction();
return this;
public int getDaysofDates(DateUtil date)
int i = 0, sum = 0;
if (this.equalTwoDates(date))
return 0;
if (this.compareDates(date))
while (!this.equalTwoDates(date))
sum++;
this.day.dayReduction();
else
while (!this.equalTwoDates(date))
sum ++;
this.day.dayIncrement();
return sum;
小结
理解类之间的相互调用关系，可以比较迅速地完成各个类中方法的设计。
7-6
题目分析
这题的思路和上一题差不多，差别在于上一题是线性的聚合关系，一个类把另一个类设为自己的属性。这题是星状的聚合关系，把DateUtil看做中心，把其他类作为自己的属性，在DateUtil类里实现对其他类的功能使用。
源码分析
类图
源码
点击查看代码
import java.util.Scanner;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
int year = 0;
int month = 0;
int day = 0;
int choice = input.nextInt();
if (choice == 1) // test getNextNDays method
int m = 0;
year = Integer.parseInt(input.next());
month = Integer.parseInt(input.next());
day = Integer.parseInt(input.next());
DateUtil date = new DateUtil(year, month, day);
if (!date.checkInputValidity())
System.out.println("Wrong Format");
System.exit(0);
m = input.nextInt();
if (m < 0)
System.out.println("Wrong Format");
System.exit(0);
System.out.print(date.getYear().getValue() + "-" + date.getMonth().getValue() + "-" + date.getDay().getValue() + " next " + m + " days is:");
System.out.println(date.getNextNDays(m).showDate());
else if (choice == 2) // test getPreviousNDays method
int n = 0;
year = Integer.parseInt(input.next());
month = Integer.parseInt(input.next());
day = Integer.parseInt(input.next());
DateUtil date = new DateUtil(year, month, day);
if (!date.checkInputValidity())
System.out.println("Wrong Format");
System.exit(0);
n = input.nextInt();
if (n < 0)
System.out.println("Wrong Format");
System.exit(0);
System.out.print(
date.getYear().getValue() + "-" + date.getMonth().getValue() + "-" + date.getDay().getValue() + " previous " + n + " days is:");
System.out.println(date.getPreviousNDays(n).showDate());
else if (choice == 3) //test getDaysofDates method
year = Integer.parseInt(input.next());
month = Integer.parseInt(input.next());
day = Integer.parseInt(input.next());
int anotherYear = Integer.parseInt(input.next());
int anotherMonth = Integer.parseInt(input.next());
int anotherDay = Integer.parseInt(input.next());
DateUtil fromDate = new DateUtil(year, month, day);
DateUtil toDate = new DateUtil(anotherYear, anotherMonth, anotherDay);
if (fromDate.checkInputValidity() && toDate.checkInputValidity())
System.out.println("The days between " + fromDate.showDate() +
" and " + toDate.showDate() + " are:"
+ fromDate.getDaysofDates(toDate));
else
System.out.println("Wrong Format");
System.exit(0);
else
System.out.println("Wrong Format");
System.exit(0);
class Day
private int value;
Day()
Day(int Value)
this.value = Value;
public int getValue()
return value;
public void setValue(int value)
this.value = value;
public void dayIncrement()
this.value++;
public void dayReduction()
this.value--;
class Month
private int value = 0;
Month ()
Month (int Value)
this.value = Value;
public int getValue()
return this.value;
public void setValue(int value)
this.value = value;
public void resetMin()
this.value = 1;
public void resetMax()
this.value = 12;
public boolean validate()
if (this.value >= 1 && this.value <= 12)
return true;
return false;
public void monthIncrement()
if (this.value == 12)
resetMin();
else
this.value ++;
public void monthReduction()
if (this.value == 1)
resetMax();
else
this.value --;
class Year
private int value = 0;
Year()
Year (int value)
this.value = value;
public int getValue ()
return this.value;
public void setValue (int value)
this.value = value;
public boolean isLeapYear ()
if ((this.value % 4 == 0 && this.value % 100 != 0) || this.value % 400 == 0)
return true;
return false;
public boolean validate ()
if (this.value >= 1820 && this.value <= 2020)
return true;
return false;
public void yearIncrement ()
this.value ++;
public void yearReduction ()
this.value --;
class DateUtil
private Year year = new Year();
private Month month = new Month();
private Day day = new Day();
private int[] mon_maxnum = 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31;
DateUtil()
DateUtil(int y, int m, int d)
year.setValue(y);
month.setValue(m);
day.setValue(d);
public Year getYear()
return this.year;
public void setYear(Year year)
this.year = year;
public Month getMonth()
return this.month;
public void setMonth(Month month)
this.month = month;
public Day getDay ()
return this.day;
public void setDay (Day day)
this.day = day;
public void setDayMin ()
day.setValue(1);
public void setDayMax ()
mon_maxnum[1] = 28;
if (this.year.isLeapYear())
mon_maxnum[1] ++;
this.day.setValue(mon_maxnum[month.getValue() - 1]);
public boolean checkInputValidity()
mon_maxnum[1] = 28;
if (this.year.isLeapYear())
mon_maxnum[1] ++;
if (this.getYear().validate() && this.getMonth().validate() && this.getDay().getValue() <= mon_maxnum[this.month.getValue() - 1] && this.getDay().getValue() >= 1)
return true;
return false;
public boolean compareDates(DateUtil date)
if(this.getYear().getValue() > date.getYear().getValue())
return true;
if(this.getYear().getValue() == date.getYear().getValue() && this.getMonth().getValue() > date.getMonth().getValue())
return true;
if(this.getMonth().getValue() == date.getMonth().getValue() && this.getDay().getValue() > date.getDay().getValue() && this.getDay().getValue() > date.getDay().getValue())
return true;
return false;
public boolean equalTwoDates(DateUtil date)
if (this.year.getValue() == date.year.getValue() && this.month.getValue() == date.month.getValue() && this.day.getValue() == date.day.getValue())
return true;
return false;
public DateUtil getNextNDays(int n)
int i;
for (i = 0; i < n; i++)
mon_maxnum[1] = 28;
if (this.year.isLeapYear())
mon_maxnum[1] ++;
if (this.day.getValue() == mon_maxnum[this.month.getValue() - 1])
if (this.month.getValue() == 12)
this.month.resetMin();
this.year.yearIncrement();
else
this.month.monthIncrement();
setDayMin();
else
this.day.dayIncrement();
return this;
public DateUtil getPreviousNDays(int n)
int i;
for (i = 0; i < n; i++)
mon_maxnum[1] = 28;
if (this.year.isLeapYear())
mon_maxnum[1] ++;
if (this.day.getValue() == 1)
if (this.month.getValue() == 1)
this.month.resetMax();
this.year.yearReduction();
else
this.month.monthReduction();
setDayMax();
else
this.day.dayReduction();
return this;
public int getDaysofDates(DateUtil date)
int i = 0, sum = 0;
if (this.equalTwoDates(date))
return 0;
if (this.compareDates(date))
while (!this.equalTwoDates(date))
sum++;
mon_maxnum[1] = 28;
if (this.year.isLeapYear())
mon_maxnum[1] ++;
if (this.day.getValue() == 1)
if (this.month.getValue() == 1)
this.month.resetMax();
this.year.yearReduction();
else
this.month.monthReduction();
setDayMax();
else
this.day.dayReduction();
else
while (!this.equalTwoDates(date))
sum++;
mon_maxnum[1] = 28;
if (this.year.isLeapYear())
mon_maxnum[1] ++;
if (this.day.getValue() == mon_maxnum[this.month.getValue() - 1])
if (this.month.getValue() == 12)
this.month.resetMin();
this.year.yearIncrement();
else
this.month.monthIncrement();
setDayMin();
else
this.day.dayIncrement();
return sum;
public String showDate()
return (this.year.getValue() + "-" + this.month.getValue() + "-" + this.day.getValue());
小结
把Month，Day，Year等作为属性后，合理调用类的方法完成方法getNextNDays(),getPreviousNDays(),getDaysofDates()的功能设计。
题目集6
7-1
题目分析
此题在第四次作业的基础上增加了异常处理的功能。
输入和上次作业大同小异，其他的差别如下
过程：
信息长度为2：(1)菜谱(读入菜谱；重复菜名，记录最后一条信息）
(2)删除点菜记录(删除记录有效，标记1，算总价时不计入，标记2，重复删除输出deduplication+序号；删除记录无效，输出delete error）
信息长度为4：(1)桌号及时间(记录桌号和时间),输出桌号
(2)点菜记录(菜名存在，输出序号+菜名+单价；菜名不存在，输出菜名+does not exist）
信息长度为5：代点菜记录(代点桌号存在，输出相关信息)
信息长度为3：
类图
源码
又是别人的代码
点击查看代码
import java.util.*;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
Menu menu = new Menu();
Table[] tablemes = new Table[10];
int dishAmount = 0;
int orderAmount = 0;
Dish dish;
int tableAmount = 0;
int count;
String[] temp;
int a1,a2,a3,a4,a5;
int flag1=0;
int mount=0;
while (true)
String string = input.nextLine();
temp = string.split(" ");
if(string.equals("end"))
break;
count = temp.length;
if (count == 2)
if (temp[1].equals("delete"))
if(tablemes[tableAmount].getFlag()==1)
else
a1 = Integer.parseInt(temp[0]);
if (tablemes[tableAmount].order.delARecordByOrderNum(a1) == 0)
System.out.println("delete error;");
else
if (!tablemes[tableAmount].order.records[a1 - 1].IsDelete())
int c = tablemes[tableAmount].order.delARecordByOrderNum(a1);
tablemes[tableAmount].order.records[a1 - 1].setDelete(true);
if(!tablemes[tableAmount].order.records[a1 - 1].d.IsSpecialDish()) tablemes[tableAmount].order.commonSum -= c;
else tablemes[tableAmount].order.specialSum -= c;
else System.out.println("deduplication " + a1);
else
if(flag1==1)
if(tablemes[tableAmount].getFlag()==1)
else System.out.println("invalid dish");
else
if(temp[1].matches("[1-9][\\\\d]*"))
if(Integer.parseInt(temp[1])<300)
a2 = Integer.parseInt(temp[1]);
menu.dishs[dishAmount] = menu.addDish(temp[0], a2);
dishAmount++;
else System.out.println(temp[0]+" price out of range "+temp[1]);
else if(temp[1].matches("0")) System.out.println(temp[0]+" price out of range "+temp[1]);
else System.out.println("wrong format");
else if(count==3)
if(temp[2].equals("T"))
if(temp[1].matches("[1-9][\\\\d]*"))
if(Integer.parseInt(temp[1])<300)
a2 = Integer.parseInt(temp[1]);
menu.dishs[dishAmount] = menu.addDish(temp[0], a2);
menu.dishs[dishAmount].setSpecialDish(true);
dishAmount++;
else System.out.println(temp[0]+" price out of range "+temp[1]);
else if(temp[1].matches("0")) System.out.println(temp[0]+" price out of range "+temp[1]);
else System.out.println("wrong format");
else System.out.println("wrong format");
else if (count == 4)
if (temp[0].equals("table"))
flag1=1;
if(temp[1].matches("[1-9][\\\\d]*"))
int num = Integer.parseInt(temp[1]);
if (num > 55)
if(tableAmount==0) tablemes[tableAmount] = new Table();
tablemes[tableAmount].setFlag(1);
System.out.println(num +" "+"table num out of range");
else
if(temp[2].matches("[1-9][\\\\d]3/[1-9][\\\\d]?/[1-9][\\\\d]?"))
String[] str = temp[2].split("/");
int year1=Integer.parseInt(str[0]);
int month1=Integer.parseInt(str[1]);
int day1=Integer.parseInt(str[2]);
int[] mon_maxNum=0,31,28,31,30,31,30,31,31,30,31,30,31;
if(month1>=1&&month1<=12)
if(day1>=1&&day1<=mon_maxNum[month1])
if(year1>=2022&&year1<=2023)
if(temp[3].matches("[1-9][\\\\d]?/[\\\\d]2/[\\\\d]2"))
tableAmount++;
orderAmount = 0;
mount=0;
tablemes[tableAmount] = new Table(temp[1], temp[2], temp[3]);
tablemes[tableAmount].setFlag(0);
tablemes[tableAmount].processTime();
tablemes[tableAmount].setCommonDiscount();
tablemes[tableAmount].setSpecialDiscount();
System.out.println("table " + temp[1] + ": ");
else
if(tableAmount==0) tablemes[tableAmount] = new Table();
tablemes[tableAmount].setFlag(1);
System.out.println("wrong format");
else
if(tableAmount==0) tablemes[tableAmount] = new Table();
tablemes[tableAmount].setFlag(1);
System.out.println("not a valid time period");
else
if(tableAmount==0) tablemes[tableAmount] = new Table();
tablemes[tableAmount].setFlag(1);
System.out.println(num +" date error");
else
if(tableAmount==0) tablemes[tableAmount] = new Table();
tablemes[tableAmount].setFlag(1);
System.out.println(num +" date error");
else
if(tableAmount==0) tablemes[tableAmount] = new Table();
tablemes[tableAmount].setFlag(1);
System.out.println("wrong format");
else
if(tableAmount==0) tablemes[tableAmount] = new Table();
tablemes[tableAmount].setFlag(1);
System.out.println("wrong format");
else
if(tablemes[tableAmount].getFlag()==1)
else
a3 = Integer.parseInt(temp[0]);
a4 = Integer.parseInt(temp[2]);
a5 = Integer.parseInt(temp[3]);
tablemes[tableAmount].order.addARecord(a3, temp[1],a4 , a5);
dish = menu.searthDish(temp[1]);
if(dish==null)
System.out.println(temp[1]+" does not exist");
if (dish != null)
if(temp[2].matches("[1-3]"))
if(temp[3].matches("[1-9]")||temp[3].matches("1[0-5]"))
if(mount==0)
tablemes[tableAmount].order.records[orderAmount].setFlag2(1);
mount++;
tablemes[tableAmount].order.records[orderAmount].d = dish;
int a = tablemes[tableAmount].order.records[orderAmount].getPrice();
System.out.println(tablemes[tableAmount].order.records[orderAmount].orderNum + " " + dish.name + " " + a);
if(!dish.IsSpecialDish()) tablemes[tableAmount].order.commonSum += a;
else tablemes[tableAmount].order.specialSum += a;
else
for(int i=orderAmount-1;i>=0;i--)
if(tablemes[tableAmount].order.records[i].flag2 ==1)
if(a3<=tablemes[tableAmount].order.records[i].orderNum)
System.out.println("record serial number sequence error");
else
tablemes[tableAmount].order.records[orderAmount].setFlag2(1);
mount++;
tablemes[tableAmount].order.records[orderAmount].d = dish;
int a = tablemes[tableAmount].order.records[orderAmount].getPrice();
System.out.println(tablemes[tableAmount].order.records[orderAmount].orderNum + " " + dish.name + " " + a);
if(!dish.IsSpecialDish()) tablemes[tableAmount].order.commonSum += a;
else tablemes[tableAmount].order.specialSum += a;
break;
else if(temp[2].matches("[1-9][\\\\d]*")) System.out.println(a3+" num out of range "+a5);
else System.out.println("wrong format");
else if(temp[2].matches("[4-9]")) System.out.println(a3+" portion out of range "+a4);
else if(temp[2].matches("[1-9][\\\\d]*")) System.out.println("not a valid portion range");
else System.out.println("wrong format");
orderAmount++;
else if (count == 5)
if(temp[0].matches("[1-9][\\\\d]*"))
int num = Integer.parseInt(temp[0]);
if (num > 55) System.out.println("Table number ："+temp[0]+" does not exist");
else
if(tablemes[tableAmount].getFlag()==1)
else
a1 = Integer.parseInt(temp[1]);
a2 = Integer.parseInt(temp[3]);
a3 = Integer.parseInt(temp[4]);
tablemes[tableAmount].order.addARecord(a1, temp[2], a2, a3);
dish = menu.searthDish(temp[2]);
if (dish != null)
tablemes[tableAmount].order.records[orderAmount].d.unit_price = dish.unit_price;
int b = tablemes[tableAmount].order.records[orderAmount].getPrice();
System.out.println(temp[1] + " table " + tablemes[tableAmount].tableNum + " pay for table " + temp[0] + " " + b);
if(!dish.IsSpecialDish()) tablemes[tableAmount].order.commonSum += b;
else tablemes[tableAmount].order.specialSum += b;
orderAmount++;
else System.out.println("wrong format");
else System.out.println("wrong format");
for (int i = 1; i < tableAmount + 1; i++)
if(tablemes[i].getCommonDiscount()>0&&tablemes[i].getSpecialDiscount()>0)
System.out.println("table " + tablemes[i].tableNum + ": "+tablemes[i].order.getTotalPrice()+" "+Math.round(tablemes[i].order.commonSum*tablemes[i].getCommonDiscount()+tablemes[i].order.specialSum*tablemes[i].getSpecialDiscount()));
else System.out.println("table " + tablemes[i].tableNum + " out of opening hours");
class Dish
String name;
int unit_price;
boolean isSpecialDish=false;
public boolean IsSpecialDish()
return isSpecialDish;
public void setSpecialDish(boolean specialDish)
isSpecialDish = specialDish;
int getPrice(int portion)
if (portion == 1) return unit_price;
else if (portion == 2) return Math.round((float) (unit_price * 1.5));
else return 2*unit_price;
class Menu
Dish[] dishs = new Dish[10];
int dishCount = 0;
Dish searthDish(String dishName)
for(int i=dishCount-1;i>=0;i--)
if(dishName.equals(dishs[i].name))
return dishs[i];
return null;
Dish addDish(String dishName,int unit_price)
Dish dish = new Dish();
dish.name = dishName;
dish.unit_price = unit_price;
dishCount++;
return dish;
class Record
int orderNum;
Dish d = new Dish();
int num = 0;
int portion;
int flag2=0;
public void setFlag2(int flag2)
this.flag2 = flag2;
boolean isDelete=false;
int getPrice()
return d.getPrice(portion)*num;
public void setDelete(boolean delete)
isDelete = delete;
public boolean IsDelete()
return isDelete;
class Order
Record[] records = new Record[10];
int count = 0;
int commonSum;
int specialSum;
void addARecord(int orderNum,String dishName,int portion,int num)
records[count] = new Record();
records[count].d.name = dishName;
records[count].orderNum = orderNum;
records[count].portion = portion;
records[count].num = num;
count++;
int getTotalPrice()
return commonSum+specialSum;
int delARecordByOrderNum(int orderNum)
if(orderNum>count||orderNum<=0)
return 0;
else
return records[orderNum - 1].getPrice();
Record findRecordByNum(int orderNum)
for (int i = count - 1; i >= 0; i--)
if (orderNum == records[i].orderNum)
return records[i];
return null;
class Table
int tableNum;
String Date;
String tableTime;
int flag=0;
public int getFlag()
return flag;
public void setFlag(int flag)
this.flag = flag;
public Table()
public Table(String tableNum, String date, String tableTime)
this.tableNum = Integer.parseInt(tableNum);
Date = date;
this.tableTime = tableTime;
int year,month,day,week,hh,mm,ss;
int sum=0;
Order order = new Order();
float commonDiscount = -1;
float specialDiscount=-1;
void processTime()
String[] temp1 = Date.split("/");
String[] temp2 = tableTime.split("/");
year = Integer.parseInt(temp1[0]);
month = Integer.parseInt(temp1[1]);
day = Integer.parseInt(temp1[2]);
Calendar date = Calendar.getInstance();
date.set(year, (month-1), day);
week = date.get(Calendar.DAY_OF_WEEK);
if(week==1)
week = 7;
else
week--;
hh = Integer.parseInt(temp2[0]);
mm = Integer.parseInt(temp2[1]);
ss = Integer.parseInt(temp2[2]);
void setCommonDiscount()
if(week>=1&&week<=5)
if(hh>=17&&hh<20)
commonDiscount =0.8F;
else if(hh==20&&mm<30)
commonDiscount =0.8F;
else if(hh==20&&mm==30&&ss==0)
commonDiscount =0.8F;
else if(hh>=11&&hh<=13||hh==10&&mm>=30)
commonDiscount =0.6F;
else if(hh==14&&mm<30)
commonDiscount =0.6F;
else if(hh==14&&mm==30&&ss==0)
commonDiscount =0.6F;
else
if(hh>=10&&hh<=20)
commonDiscount = 1.0F;
else if(hh==9&&mm>=30)
commonDiscount = 1.0F;
else if(hh==21&&mm<30||hh==21&&mm==30&&ss==0)
commonDiscount = 1.0F;
void setSpecialDiscount()
if(week>=1&&week<=5)
if(hh>=17&&hh<20)
specialDiscount =0.7F;
else if(hh==20&&mm<30)
specialDiscount =0.7F;
else if(hh==20&&mm==30&&ss==0)
specialDiscount =0.7F;
else if(hh>=11&&hh<=13||hh==10&&mm>=30)
specialDiscount =0.7F;
else if(hh==14&&mm<30)
specialDiscount =0.7F;
else if(hh==14&&mm==30&&ss==0)
specialDiscount =0.7F;
else
if(hh>=10&&hh<=20)
specialDiscount = 1.0F;
else if(hh==9&&mm>=30)
specialDiscount = 1.0F;
else if(hh==21&&mm<30||hh==21&&mm==30&&ss==0)
specialDiscount = 1.0F;
float getCommonDiscount()
return commonDiscount;
float getSpecialDiscount()
return specialDiscount;
小结
我一开始只写了一桌的情况，没有加循环进去，导致后面修改时一直有错误出现，而且我判断循环跳出的条件存在问题，主要还是没理清楚这些异常处理的先后关系和输出的先后关系，后面就没办法进行下去了。
三.踩坑心得
第四次作业
7-3(去掉重复的数据)
错误点
题目要求：读入数据，检查是否有重复的数据。如果有，去掉所有重复的数字。最后按照输入顺序输出没有重复数字的数据。
Hashset和Arrays.sort()都会对数据进行排序，所以输出时不会按照原数据的顺序输出
ArrayList遍历时间复杂度是O(n),list.contains()很慢
错误代码
点击查看代码
import java.util.*;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
int n = input.nextInt();
int i;
int[] a = new int[n];
for (i = 0; i < n; i++)
a[i] = input.nextInt();
Arrays.sort(a);
for (i = 0; i < n - 1; i++)
if(a[i] != a[i + 1])
System.out.print(a[i] + " ");
System.out.print(a[n - 1]);
正确代码
点击查看代码
import java.util.*;
import java.util.HashSet;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
int n = input.nextInt();
int i;
int[] a = new int[n];
HashSet<Integer> sites1 = new HashSet<>();
HashSet<Integer> sites2 = new HashSet<>();
for (i = 0; i < n; i++)
a[i] = input.nextInt();
sites2.add(a[i]);
int size = sites2.size();
for (i = 0; i < n - 1; i++)
if(!sites1.contains(a[i]) )
System.out.print(a[i]);
sites1.add(a[i]);
if((size == 1 && i == 0) || size == sites1.size())
continue;
System.out.print(" ");
if(!sites1.contains(a[n - 1]))
System.out.print(a[n - 1]);
7-4(单词统计与排序)
错误点
重复输出，且忽略长文本中的文本换行情况
错误代码
点击查看代码
import java.util.Arrays;
import java.util.Scanner;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
String str1 = new String();
str1 = input.nextLine().replaceAll(",", "");
str1 = str1.replaceAll("\\\\."," ");
String[] str = str1.split(" ");
Arrays.sort(str,String.CASE_INSENSITIVE_ORDER);
int i, j;
int[] a = new int[str.length];
int max = 0;
for(i = 0; i< str.length; i++)
a[i] = str[i].length();
if(max < a[i])
max = a[i];
for(i = max; i >= 0; i--)
for (j = 0; j < str.length; j ++)
if(i == a[j])
System.out.println(str[j]);
正确代码
点击查看代码
import java.util.Arrays;
import java.util.HashSet;
import java.util.Scanner;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
String str1 = new String();
str1 = input.nextLine().replaceAll(",", "");
str1 = str1.replaceAll("\\\\.", " ");
str1 = str1.replaceAll("\\n","");
String[] str = str1.split(" ");
HashSet<String> sites = new HashSet<String>();
Arrays.sort(str, String.CASE_INSENSITIVE_ORDER);
int i, j;
int[] a = new int[str.length];
int max = 0;
//String str_ = "\\n";
//System.out.println(str_);
for (i = 0; i < str.length; i++)
a[i] = str[i].length();
if (max < a[i])
max = a[i];
for (i = max; i > 0; i--) //把i >= 0改为>
for (j = 0; j < a.length; j++)
if (i == a[j] && !sites.contains(str[j]))
System.out.println(str[j]);
sites.add(str[j]);
7-6(GPS测绘中度分秒转换)
错误点
输出时用了System.out.printf("%d°%d′%.2f″ = %.6f",this.degrees, this.minutes, this.seconds,this.convension());
限制了this.seconds保留两位小数
错误代码
点击查看代码
import java.util.Scanner;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
LatitudeConversion l = new LatitudeConversion(input.nextInt(), input.nextInt(), input.nextFloat());
l.convension();
l.print();
class LatitudeConversion
private int degrees;
private int minutes;
private float seconds;
LatitudeConversion()
LatitudeConversion(int degrees, int minutes, float seconds)
this.degrees = degrees;
this.minutes = minutes;
this.seconds = seconds;
public void setDegrees(int degrees)
this.degrees = degrees;
public void setMinutes(int minutes)
this.minutes = minutes;
public void setSeconds(float seconds)
this.seconds = seconds;
public int getDegrees()
return this.degrees;
public int getMinutes()
return this.minutes;
public float getSeconds()
return this.seconds;
public double convension()
return this.degrees + this.minutes / 60.0 + this.seconds / 3600.0;//this.minutes / 60.0
public void print()
System.out.printf("%d°%d′%.2f″ = %.6f",this.degrees, this.minutes, this.seconds,this.convension());
正确代码
点击查看代码
import java.util.Scanner;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
LatitudeConversion l = new LatitudeConversion(input.nextInt(), input.nextInt(), input.nextFloat());
l.convension();
l.print();
class LatitudeConversion
private int degrees;
private int minutes;
private float seconds;
LatitudeConversion()
LatitudeConversion(int degrees, int minutes, float seconds)
this.degrees = degrees;
this.minutes = minutes;
this.seconds = seconds;
public void setDegrees(int degrees)
this.degrees = degrees;
public void setMinutes(int minutes)
this.minutes = minutes;
public void setSeconds(float seconds)
this.seconds = seconds;
public int getDegrees()
return this.degrees;
public int getMinutes()
return this.minutes;
public float getSeconds()
return this.seconds;
public double convension()
return this.degrees + this.minutes / 60.0 + this.seconds / 3600.0;//this.minutes / 60.0
public void print()
System.out.print(this.degrees + "°" + this.minutes + "′" + this.seconds + "″ = ");
System.out.printf("%.6f",this.convension());
7-7(判断两个日期的先后，计算间隔天数、周数）
错误点
date1.until(date2)只能同一个月相差的天数
错误代码
点击查看代码
import java.time.LocalDate;
import java.util.*;
import java.time.Period;
public class Main
public static void main(String[] args)
Scanner input = new Scanner(System.in);
String[] str11 = input.nextLine().split("-");
String[] str22 = input.nex团队作业7——第二次项目冲刺（Beta版本)
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