Lensovet: Lensovet moved page CS/61b/Homework/hw2/Date.java to Computer Science/61b/Homework/hw2/Date.java

2023-02-20T03:51:34Z

Lensovet moved page CS/61b/Homework/hw2/Date.java to Computer Science/61b/Homework/hw2/Date.java

Lensovet: moved CS 61b/Homework/hw2/Date.java to CS/61b/Homework/hw2/Date.java: fix cs 61b hierarchy

2010-11-14T06:00:19Z

moved CS 61b/Homework/hw2/Date.java to CS/61b/Homework/hw2/Date.java: fix cs 61b hierarchy

Lensovet at 19:52, 22 May 2007

2007-05-22T19:52:45Z

New page

{{code}}
/* Date.java */

import java.io.*;

class Date {

/* Put your private data fields here. */
private int month;
private int day;
private int year;
/** Constructs a date with the given month, day and year. If the date is
* not valid, the entire program will halt with an error message.
* @param month is a month, numbered in the range 1...12.
* @param day is between 1 and the number of days in the given month.
* @param year is the year in question, with no digits omitted.
*/
public Date(int month, int day, int year) {
if (isValidDate(month, day, year)) {
this.month = month;
this.day = day;
this.year = year;
} else {
System.out.println("You have entered in invalid date");
System.exit(0); }
}

/** Constructs a Date object corresponding to the given string.
* @param s should be a string of the form "month/day/year" where month must
* be one or two digits, day must be one or two digits, and year must be
* between 1 and 4 digits. If s does not match these requirements or is not
* a valid date, the program halts with an error message.
*/
public Date(String s) {
int[] datearray = new int[3];
for (int i=0; i<3; i++)
{ datearray[i] = Integer.parseInt(s.split("/", 3)[i]); }
if (isValidDate(datearray[0], datearray[1], datearray[2])) {
this.month = datearray[0];
this.day = datearray[1];
this.year = datearray[2];
} else {
System.out.println("You have entered in invalid date");
System.exit(0); }
}

/** Checks whether the given year is a leap year.
* @return true if and only if the input year is a leap year.
*/
public static boolean isLeapYear(int year) {
if (year%400 != 0 && year%4 == 0) { return true; }
else { return false; }
}

/** Returns the number of days in a given month.
* @param month is a month, numbered in the range 1...12.
* @param year is the year in question, with no digits omitted.
* @return the number of days in the given month.
*/
public static int daysInMonth(int month, int year) {
if (isLeapYear(year) && month == 2) { return 29; }
switch (month) {
case 1: return 31;
case 2: return 28;
case 3: return 31;
case 4: return 30;
case 5: return 31;
case 6: return 30;
case 7: return 31;
case 8: return 31;
case 9: return 30;
case 10: return 31;
case 11: return 30;
case 12: return 31;
// default: System.out.println("Invalid month");
}
return 0;
}

/** Checks whether the given date is valid.
* @return true if and only if month/day/year constitute a valid date.
*
* Years prior to A.D. 1 are NOT valid.
*/
public static boolean isValidDate(int month, int day, int year) {
if (month>12 || month <1 || day<1 || day>daysInMonth(month, year) || year<1) { return false; }
else { return true; }
}

/** Returns a string representation of this date in the form month/day/year.
* The month, day, and year are printed in full as integers; for example,
* 12/7/2006 or 3/21/407.
* @return a String representation of this date.
*/
public String toString() {
return (this.month + "/" + this.day + "/" + this.year);
}

/** Determines whether this Date is before the Date d.
* @return true if and only if this Date is before d.
*/
public boolean isBefore(Date d) {
if((this.dayInYear() < d.dayInYear() && this.year == d.year) || this.year < d.year) { return true; }
// if (this.dayInYear() > d.dayInYear() || this.dayInYear() == d.dayInYear() || this.year > d.year) { return false; }
else { return false; }
}

/** Determines whether this Date is after the Date d.
* @return true if and only if this Date is after d.
*/
public boolean isAfter(Date d) {
return d.isBefore(this);
}

/** Returns the number of this Date in the year.
* @return a number n in the range 1...366, inclusive, such that this Date
* is the nth day of its year. (366 is only used for December 31 in a leap
* year.)
*/
public int dayInYear() {
int noOfdays = 0;
for (int tmonth = 1; month>tmonth; tmonth++) {
noOfdays = noOfdays + daysInMonth(tmonth, this.year); }
noOfdays = noOfdays + this.day;
return noOfdays; }

/** Determines the difference in days between d and this Date. For example,
* if this Date is 12/15/1997 and d is 12/14/1997, the difference is 1.
* If this Date occurs before d, the result is negative.
* @return the difference in days between d and this date.
*/
public int difference(Date d) {
if (this.year == d.year) { return d.dayInYear() - this.dayInYear(); }
else if (this.year < d.year) {
int days = 0;
for (int start = this.year+1; start<d.year; start++) {
days = days + new Date(12, 31, start).dayInYear(); }
return (-1 * (d.dayInYear() + new Date(12,31,this.year).dayInYear() - this.dayInYear() + days)); }
else {
int days = 0;
for (int start = d.year+1; start<this.year; start++) {
days = days + new Date(12, 31, start).dayInYear(); }
return this.dayInYear() + new Date(12,31,d.year).dayInYear() - d.dayInYear() + days; }
}

public static void main(String[] argv) {
System.out.println("\nTesting constructors.");
Date d1 = new Date(1, 1, 1);
System.out.println("Date should be 1/1/1: " + d1);
d1 = new Date("2/4/2");
System.out.println("Date should be 2/4/2: " + d1);
d1 = new Date("2/28/2000");
System.out.println("Date should be 2/28/2000: " + d1);
d1 = new Date("2/29/1904");
System.out.println("Date should be 2/29/1904: " + d1);

d1 = new Date(12, 31, 1975);
System.out.println("Date should be 12/31/1975: " + d1);
Date d2 = new Date("1/1/1976");
System.out.println("Date should be 1/1/1976: " + d2);
Date d3 = new Date("1/2/1976");
System.out.println("Date should be 1/2/1976: " + d3);

Date d4 = new Date("2/27/1977");
Date d5 = new Date("8/31/2110");

/* I recommend you write code to test the isLeapYear function! */

System.out.println("\nTesting before and after.");
System.out.println(d2 + " after " + d1 + " should be true: " +
d2.isAfter(d1));
System.out.println(d3 + " after " + d2 + " should be true: " +
d3.isAfter(d2));
System.out.println(d1 + " after " + d1 + " should be false: " +
d1.isAfter(d1));
System.out.println(d1 + " after " + d2 + " should be false: " +
d1.isAfter(d2));
System.out.println(d2 + " after " + d3 + " should be false: " +
d2.isAfter(d3));

System.out.println(d1 + " before " + d2 + " should be true: " +
d1.isBefore(d2));
System.out.println(d2 + " before " + d3 + " should be true: " +
d2.isBefore(d3));
System.out.println(d1 + " before " + d1 + " should be false: " +
d1.isBefore(d1));
System.out.println(d2 + " before " + d1 + " should be false: " +
d2.isBefore(d1));
System.out.println(d3 + " before " + d2 + " should be false: " +
d3.isBefore(d2));

System.out.println("\nTesting difference.");
System.out.println(d1 + " - " + d1 + " should be 0: " +
d1.difference(d1));
System.out.println(d2 + " - " + d1 + " should be 1: " +
d2.difference(d1));
System.out.println(d3 + " - " + d1 + " should be 2: " +
d3.difference(d1));
System.out.println(d3 + " - " + d4 + " should be -422: " +
d3.difference(d4));
System.out.println(d5 + " - " + d4 + " should be 48762: " +
d5.difference(d4));
}
}

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Computer Science/61b/Homework/hw2/Date.java - Revision history

Lensovet: Lensovet moved page CS/61b/Homework/hw2/Date.java to Computer Science/61b/Homework/hw2/Date.java

Lensovet: moved CS 61b/Homework/hw2/Date.java to CS/61b/Homework/hw2/Date.java: fix cs 61b hierarchy

Lensovet at 19:52, 22 May 2007