作業DISPLAY4.11，4.12

package aaa;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class DateSixthTry
{
private String month;
private int day;
private int year;

public void setDate(int monthInt, int day, int year)
{
if (dateOK(monthInt, day, year))
{
this.month = monthString(monthInt);
this.day = day;
this.year = year;
}
else
{
System.out.println("Fatal Error");
System.exit(0);
}
}

public void setDate(String monthString, int day, int year) {
if (dateOK(monthString, day, year)) {
this.month = monthString;
this.day = day;
this.year = year;
}
else {
System.out.println("Fatal Error");
System.exit(0);
}
}

public void setDate(int year)
{
setDate(1, 1, year);
}

private boolean dateOK(int monthInt, int dayInt, int yearInt) {
return ( (monthInt >= 1) &&amp;(monthInt <= 12) && (dayInt >= 1) &&(dayInt >=1 )&& (dayInt <= 31) && (yearInt >= 1000) && (yearInt <= 9999)); } private boolean dateOK(String monthString, int dayInt, int yearInt) { return (monthOK(monthString) &&amp;(dayInt >= 1) && (dayInt <= 31) && (yearInt >= 1000) && (yearInt <= 9999)); } private boolean monthOK(String month) { return (month.equals("January") || month.equals("February") || month.equals("March") || month.equals("April") || month.equals("May") || month.equals("June") || month.equals("July") || month.equals("August") || month.equals("September") || month.equals("October") || month.equals("November") || month.equals("December")); } public void readInput() throws IOException { boolean tryAgain = true; BufferedReader keyboard = new BufferedReader(new InputStreamReader(System. in)); while (tryAgain) { System.out.println("Enter month, day, and year."); System.out.println("Do not use a comma."); String monthInput = keyboard.readLine(); int dayInput = keyboard.read(); int yearInput = keyboard.read(); if (dateOK(monthInput, dayInput, yearInput)) { setDate(monthInput, dayInput, yearInput); tryAgain = false; } else System.out.println("Illegal date. Reenter input."); } } public void writeOutput() { System.out.println(month + " " + day + ", " + year); } public void setMonth(int month) { if ( (month <= 0) || (month > 12))
{
System.out.println("Fatal Error");
System.exit(0);
}
else
this.month = monthString(month);
}

public void setMonth(String month) {
this.month = month;
}

public void setDay(int day) {
if ( (day <= 0) || (day > 31)) {
System.out.println("Fatal Error");
System.exit(0);
}
else
this.day = day;
}

public void setYear(int year) {
if ( (year<=9999)||(year>=1000))
{
System.out.println("Fatal Error");
System.exit(0);
}
else
this.year = year;
}

public boolean equals(DateSixthTry otherDate)
{
return ( (month.equalsIgnoreCase(otherDate.month))&&amp; (day == otherDate.day) && (year == otherDate.year));
}

public boolean precedes(DateSixthTry otherDate)
{
return ( (year < otherDate.year) ||
(year == otherDate.year &&amp; getMonth() < otherDate.getMonth()) ||
(year == otherDate.year && month.equals(otherDate.month)
&&amp; day < otherDate.day));
}

public String toString() {
return (month + " " + day + ", " + year);
}

public int getDay() {
return day;
}

public int getYear() {
return year;
}

public int getMonth() {
if (month.equalsIgnoreCase("January"))
return 1;
else if (month.equalsIgnoreCase("February"))
return 2;
else if (month.equalsIgnoreCase("March"))
return 3;
else if (month.equalsIgnoreCase("April"))
return 4;
else if (month.equalsIgnoreCase("May"))
return 5;
else if (month.equals("June"))
return 6;
else if (month.equalsIgnoreCase("July"))
return 7;
else if (month.equalsIgnoreCase("August"))
return 8;
else if (month.equalsIgnoreCase("September"))
return 9;
else if (month.equalsIgnoreCase("October"))
return 10;
else if (month.equalsIgnoreCase("November"))
return 11;
else if (month.equalsIgnoreCase("December"))
return 12;
else {
System.out.println("Fatal Error");
System.exit(0);
return 0;
}
}

private String monthString(int monthNumber) {
switch (monthNumber) {
case 1:
return "January";
case 2:
return "February";
case 3:
return "March";
case 4:
return "April";
case 5:
return "May";
case 6:
return "June";
case 7:
return "July";
case 8:
return "August";
case 9:
return "September";
case 10:
return "October";
case 11:
return "November";

case 12:
return "December";
default:
System.out.println("Fatal Error");
System.exit(0);
return "Error";
}
}
}
____________________________________________________________________

package aaa;

public class OverloadedingDemo {
public static void main(String[] args) {
DateSixthTry date1 = new DateSixthTry(),
date2 = new DateSixthTry(),
date3 = new DateSixthTry();
date1.setDate(1, 2, 2007);
date1.setMonth(3);
date2.setDate("February", 2, 2007);
date2.setMonth("April");
date3.setDate(2007);
System.out.println(date1);
System.out.println(date2);
System.out.println(date3);
}
}
}