PTA 4-6次总结

04：这次题目集主要学习了：使用LinkedHashSet删除arraylist中的重复数据，封装，了解Scanner类中nextLine(等方法、String类中split(等方法、Integer类中parseInt(等方法的用法，了解LocalDate类中of(、isAfter(、isBefore(、until(等方法的使用规则，了解ChronoUnit类中DAYS、WEEKS、MONTHS等单位的用法。题目的数目较多，但只有少数题目难度较大，比如菜单程序以及日期问题。

06：这次题目只有一个菜单程序，难度较大。

题目集4：7-1：这道题是大学以来见过的最头疼的题，由于本次题目集题量大、难度高、时间紧，我选择了先完成较简单的题目，而最难的菜单题选择了留到后面，等到结束也没能做出来，后面才知道老师把第一个题的难度设定的这样高，是为了提升我的能力，告诉我作为软件工程师不能怕困难，要迎难而上，我也下定决心做一个不怕困难的人。

import java.util.Scanner;

public static void main(String[] args {
Scanner input = new Scanner(System.in;
int year = 0;
int month = 0;
int day = 0;

if (choice == 1 { // test getNextNDays method
int m = 0;
year = Integer.parseInt(input.next(;
month = Integer.parseInt(input.next(;
day = Integer.parseInt(input.next(;

if (!date.checkInputValidity( {
System.out.println("Wrong Format";
System.exit(0;
}

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(;

if (!date.checkInputValidity( {
System.out.println("Wrong Format";
System.exit(0;
}

if (n < 0 {
System.out.println("Wrong Format";
System.exit(0;
}

}
else if (choice == 3 { //test getDaysofDates method
year = Integer.parseInt(input.next(;
month = Integer.parseInt(input.next(;
day = Integer.parseInt(input.next(;

int anotherMonth = Integer.parseInt(input.next(;
int anotherDay = Integer.parseInt(input.next(;

DateUtil toDate = new DateUtil(anotherYear, anotherMonth, anotherDay;

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 DateUtil{
Day day=new Day(;
public DateUtil({
}
public DateUtil(int d,int m,int y{
this.day.value=d;
this.day.month.value=m;
this.day.month.year.value=y;
}
public int getDay( {
return day.value;
}
public void setDay(Day d {
this.day=d;
}
public boolean checkInputValidity({//检测输入的年、月、日是否合法
if(day.month.year.validate(&&day.month.validate(&&day.validate({
if((day.month.year.isLeapYear(getDay(&&day.month.value==2&&day.month.value<=29||day.validate(
return true;
else
return false;
}
else
return false;
}
public DateUtil getNextNDays(int m{//取得year-month-day的下n天日期
for(int i=0;i<m;i++{//用下一天循环
if(day.month.value==1||day.month.value==3||day.month.value==5||day.month.value==7||day.month.value==8||day.month.value==10||day.month.value==12{
if(day.month.value!=12&&day.value<31
day.dayIncrement(;
else if(day.month.value<12&&day.value==31{
day.restMin(;
day.month.monthIncrement(;
}
else if(day.month.value==12&&day.value==31{
day.restMin(;
day.month.restMin(;
day.month.year.yearIncrement(;
}
else
day.dayIncrement(;
}
else if(day.month.value==2{
if((day.month.year.isLeapYear(getDay(&&day.value==29||(!day.month.year.isLeapYear(getDay(&&day.value==28{
day.month.value=3;
day.dayIncrement(;
}
else
day.dayIncrement(;
}
else if(day.month.value==4||day.month.value==6||day.month.value==9||day.month.value==11{
if(day.value<30
day.dayIncrement(;
else if(day.value==30{
day.restMin(;
day.month.monthIncrement(;
}
}
}

}
public DateUtil getPreviousNDays(int n{//取得year-month-day的前n天日期
for(int i=0;i<n;i++{//用上一天循环
if(day.month.value==2||day.month.value==4||day.month.value==6||day.month.value==8||day.month.value==9||day.month.value==11||day.month.value==1{
if(day.month.value==1&&day.value==1 {
day.month.year.yearReduction(;
day.month.restMax(;
day.restMax(;
}
else if(day.value==1{
day.restMax(;
day.month.monthReduction(;
}
else
day.dayReduction(;
}
else if(day.month.value==3{
if(day.month.year.isLeapYear(getDay(&&day.value==1{
day.month.value=2;
day.value=29;
}
else if(!day.month.year.isLeapYear(getDay(&&day.value==1 {
day.month.value=2;
day.value=28;
}
else
day.dayReduction(;
}
else if(day.month.value==5||day.month.value==7||day.month.value==10||day.month.value==12{
if(day.value==1 {
day.month.monthReduction(;
day.value=30;
}
else
day.dayReduction(;
}
}
return new DateUtil(day.month.year.value,day.month.value,day.value;
}
public boolean compareDates(DateUtil date{//比较当前日期与date的大小（先后）
if(date.day.month.year.value<this.day.month.year.value {
return false;
}
else if(date.day.month.year.value==this.day.month.year.value&&date.day.month.value<this.day.month.value {
return false;
}
else if(date.day.month.year.value==this.day.month.year.value&&date.day.month.value==this.day.month.value&&date.day.value<this.day.value {
return false;
}
else
return true;
}
public boolean equalTwoDates(DateUtil date{//判断两个日期是否相等
if(this.day.month.year.value==date.day.month.year.value&&this.day.month.value==date.day.month.value&&this.day.value==date.day.value
return true;
return false;
}
public int getDaysofDates(DateUtil date{//求当前日期与date之间相差的天数
DateUtil fromDate=this;
DateUtil toDate=date;
int i=0,j=0,k=0;
int[] mon_maxnum=new int[] {0,31,28,31,30,31,30,31,31,30,31,30,31};
if(this.equalTwoDates(date
return 0;
else if(!this.compareDates(date {
fromDate=date;
toDate=this;
}
for(i=fromDate.day.month.year.value+1;i<toDate.day.month.year.value;i++ {
if(day.month.year.isLeapYear(i
j=366;
else j=365;
k=k+j;
}

mon_maxnum[2]=29;
else mon_maxnum[2]=28;
int p=fromDate.day.month.value;
for (i=fromDate.day.month.value;i<=12;i++{
if(i==p{
k=k+day.mon_maxnum[i]-fromDate.day.value;
}
else k=k+mon_maxnum[i];
}
int t=toDate.day.month.value;
if(day.month.year.isLeapYear(toDate.day.month.year.value&&toDate.day.month.value>2
mon_maxnum[2]=29;
else mon_maxnum[2]=28;
for (i=1;i<=toDate.day.month.value;i++{
if(i==t{
k=k+toDate.day.value;
}
else k=k+mon_maxnum[i];
}
return k;
}
public String showDate({//以“year-month-day”格式返回日期值
return this.day.month.year.value+"-"+this.day.month.value+"-"+this.day.value;
}
}
class Day{
int value;//day
int[] mon_maxnum = {0,31,28,31,30,31,30,31,31,30,31,30,31};
Month month=new Month(;
public Day( {}
public Day(int yearValue,int monthValue,int dayValue{
}
public int getValue( {
return value;
}
public void setValue(int value {
this.value = value;
}
public Month getMonth( {
return month;
}
public void setMonth(Month value {
this.month = value;
}
public void restMin( {
value = 1;
}
public void restMax( {
value = mon_maxnum[month.value];
}
public boolean validate( {
if(value>=1&&value<=31 {
if((month.year.isLeapYear(month.year.value&&month.value==2&&value<=29||value<=mon_maxnum[month.value]
return true;
else
return false;
}
else
return false;
}
public void dayIncrement( {}
public void dayReduction( {}
}
class Month{
int value;
Year year=new Year(;
public Month( {}
public Month(int yearValue,int 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 restMin( {
value = 1;
}
public void restMax( {
value = 12;
}
public boolean validate( {
if(value>=1&&value<=12
return true;
else
return false;
}
public void monthIncrement( {
value=value+1;
}
public void monthReduction( {
value=value-1;
}
}
class Year{
int value;
public Year( {}
public Year(int yearValue{
}
public int getValue( {
return value;
}
public void setValue(int value {
this.value = value;
}
public boolean isLeapYear(int year{//判断year是否为闰年
if ((year % 4 == 0 && year % 100 != 0 || year % 400 == 0
return true;
else
return false;
}
public boolean validate( {
if(value>=1900&&value<=2050
return true;
else
return false;
}
public void yearIncrement( {
value=value+1;
}
public void yearReduction( {
value=value-1;
}
}

7-6：

public class Main {
public static void main(String[] args {
Scanner input = new Scanner(System.in;
int year = 0;
int month = 0;
int day = 0;