Introduction
I will write a small function related to the calendar using some basic Java syntax.
英语和Java初学者，现在用文章记录我的学习/练习过程，如果有人看到我的任何错误或者有建议的地方可以帮我指出来么🥺
Details & Steps
Details
- From January 01, 1900(Monday)
- When I input a year and a month, this program could output this monthly calendar
Steps
- Importing the package of inputs.
import java.util.Scanner;
- Calculating the total days, from 1900 to the previous years of the year of input (because the year of input isn't a complete year).
Scanner scanner = new Scanner(System.in);
System.out.println("Please input the year:");
int year = scanner.nextInt();
System.out.println("Please input the month:");
int month = scanner.nextInt();
final int initialYear = 1900;
int totalDays = 0;
// Judging this year and month are leap year and leap month or not
boolean isLeapYear = (year / 4 == 0 && year / 100 != 0) || (year / 400 == 0);
for (int i = initialYear; i < year; i++) {
// Judging this year and month are leap year and leap month or not
totalDays += ((i % 4 == 0 && i % 100 != 0) || (i % 400 == 0)) ? 366 : 365;
}
- Calculating the total days, from the beginning of the year of input to the month of input.
for (int i = 1; i < month; i++) {
if (i == 2) {
totalDays += isLeapYear ? 29 : 28;
} else if (i == 1 || i == 3 || i == 5 || i == 7 || i == 8 || i == 10 || i == 12) {
totalDays += 31;
} else {
totalDays += 30;
}
}
- Calculating the first day of the month of input (what day is it today: total days % 7 + 1).
int dayOfWeek = totalDays % 7 + 1;
- Calculating the number of days of the month of input.
int monthDays = 0;
if (month == 2) {
monthDays = isLeapYear ? 29 : 28;
} else if (month == 4 || month == 6 || month == 9 || month == 11) {
monthDays = 30;
} else {
monthDays = 31;
}
- Outputting the header of table.
// I use ‘/t’ for adding spacing
System.out.println("Mon\t Tue\t Wed\t Thu\t Fri\t Sat\t Sun\t");
- Designing spacing.
// Matching date and week, aligning them
for (int i = 1; i < dayOfWeek; i++) {
System.out.print("\t");
}
for (int i = 1; i <= monthDays; i++) {
System.out.print(i + "\t");
// At the end of week, new line
if (((dayOfWeek - 1) + i) % 7 == 0) {
System.out.println();
}
}
Total
package com.practice;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Please input the year:");
int year = scanner.nextInt();
System.out.println("Please input the month:");
int month = scanner.nextInt();
final int initialYear = 1900;
int totalDays = 0;
int monthDays = 0;
boolean isLeapYear = (year / 4 == 0 && year / 100 != 0) || (year / 400 == 0);
for (int i = initialYear; i < year; i++) {
// Judging this year and month are leap year and leap month or not
totalDays += ((i % 4 == 0 && i % 100 != 0) || (i % 400 == 0)) ? 366 : 365;
}
for (int i = 1; i < month; i++) {
if (i == 2) {
totalDays += isLeapYear ? 29 : 28;
} else if (i == 1 || i == 3 || i == 5 || i == 7 || i == 8 || i == 10 || i == 12) {
totalDays += 31;
} else {
totalDays += 30;
}
}
int dayOfWeek = totalDays % 7 + 1;
if (month == 2) {
monthDays = isLeapYear ? 29 : 28;
} else if (month == 4 || month == 6 || month == 9 || month == 11) {
monthDays = 30;
} else {
monthDays = 31;
}
// I use ‘/t’ for adding spacing
System.out.println("Mon\t Tue\t Wed\t Thu\t Fri\t Sat\t Sun\t");
// Matching date and week, aligning them
for (int i = 1; i < dayOfWeek; i++) {
System.out.print("\t");
}
for (int i = 1; i <= monthDays; i++) {
System.out.print(i + "\t");
// At the end of week, new line
if (((dayOfWeek - 1) + i) % 7 == 0) {
System.out.println();
}
}
}
}
