如何让java将选择应用于闰年？规则是每4年有一个从0开始的闰年。我做的布尔值是leapYear = year％4 == 0但是当我输入leapYear时，例如4，if语句（3月）用leapYear输出空行。这是代码：
public static void main(String[] args) {
// create a scanner
Scanner input = new Scanner(System.in);
//prompt user to enter year and first weekday
System.out.println("Enter a year");
int year = input.nextInt();
System.out.println("Enter first weekday of year e.g.: 0 for Sunday");
int weekDay = input.nextInt();
int i;
int jan = 31;
int feb = 28;
int mar = 31;
int apr = 30;
int may = 31;
int jun = 30;
int jul = 31;
int aug = 31;
int sep = 30;
int oct = 31;
int nov = 30;
int dec = 31;
// leap year
boolean leapYear = year % 4 == 0;
if (leapYear) feb += 1;
System.out.println("January " + year);
System.out.println("________________________________");
System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
if (weekDay == 1) System.out.printf("%4s", " ");
if (weekDay == 2) System.out.printf("%8s", " ");
if (weekDay == 3) System.out.printf("%12s", " ");
if (weekDay == 4) System.out.printf("%16s", " ");
if (weekDay == 5) System.out.printf("%20s", " ");
if (weekDay == 6) System.out.printf("%24s", " ");
for (i = 1; i <= jan; i++) {
System.out.printf("%4d", i);
if (weekDay == 0 && i % 7 == 0) System.out.println("\n");
if (weekDay == 1 && (i == 6 || i == 13 || i == 20 || i == 27)) System.out.println("\n");
if (weekDay == 2 && (i == 5 || i == 12 || i == 19 || i == 26)) System.out.println("\n");
if (weekDay == 3 && (i == 4 || i == 11 || i == 18 || i == 25)) System.out.println("\n");
if (weekDay == 4 && (i == 3 || i == 10 || i == 17 || i == 24)) System.out.println("\n");
if (weekDay == 5 && (i == 2 || i == 9 || i == 16 || i == 23 || i == 30)) System.out.println("\n");
if (weekDay == 6 && (i == 1 || i == 8 || i == 15 || i == 22 || i == 29)) System.out.println("\n");
}
System.out.println("\n");
System.out.println("February " + year);
System.out.println("________________________________");
System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
if (weekDay == 0) System.out.printf("%12s", " ");
if (weekDay == 1) System.out.printf("%16s", " ");
if (weekDay == 2) System.out.printf("%20s", " ");
if (weekDay == 3) System.out.printf("%24s", " ");
if (weekDay == 5) System.out.printf("%4s", " ");
if (weekDay == 6) System.out.printf("%8s", " ");
for (i = 1; i <= feb; i++) {
System.out.printf("%4d", i);
if (weekDay == 0 && (i == 4 || i == 11 || i == 18 || i == 25)) System.out.println("\n");
if (weekDay == 1 && (i == 3 || i == 10 || i == 17 || i == 24)) System.out.println("\n");
if (weekDay == 2 && (i == 2 || i == 9 || i == 16 || i == 23)) System.out.println("\n");
if (weekDay == 3 && (i == 1 || i == 8 || i == 15 || i == 22)) System.out.println("\n");
if (weekDay == 4 && i % 7 == 0) System.out.println("\n");
if (weekDay == 5 && (i == 6 || i == 13 || i == 20 || i == 27)) System.out.println("\n");
if (weekDay == 6 && (i == 5 || i == 12 || i == 19 || i == 26)) System.out.println("\n");
}
System.out.println("\n");
System.out.println("March " + year);
System.out.println("________________________________");
System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
if (leapYear) {
if (weekDay == 0) System.out.printf("%4s", " ");
if (weekDay == 1) System.out.printf("%8s", " ");
if (weekDay == 2) System.out.printf("%12s", " ");
if (weekDay == 3) System.out.printf("%16s", " ");
if (weekDay == 5) System.out.printf("%20s", " ");
if (weekDay == 6) System.out.printf("%24s", " ");
for (i = 1; i <= mar; i++) {
if (weekDay == 6 && (i == 4 || i == 11 || i == 18 || i == 25)) System.out.println("\n");
if (weekDay == 0 && (i == 3 || i == 10 || i == 17 || i == 24)) System.out.println("\n");
if (weekDay == 1 &&(i == 2 || i == 9 || i == 16 || i == 23 || i == 30)) System.out.println("\n");
if (weekDay == 2 &&(i == 1 || i == 8 || i == 15 || i == 22 || i == 29)) System.out.println("\n");
if (weekDay == 3 && i % 7 == 0) System.out.println("\n");
if (weekDay == 4 && (i == 6 || i == 13 || i == 20 || i == 27)) System.out.println("\n");
if (weekDay == 5 && (i == 5 || i == 12 || i == 19 || i == 26)) System.out.println("\n");
}
}
else {
if (weekDay == 0) System.out.printf("%12s", " ");
if (weekDay == 1) System.out.printf("%16s", " ");
if (weekDay == 2) System.out.printf("%20s", " ");
if (weekDay == 3) System.out.printf("%24s", " ");
if (weekDay == 5) System.out.printf("%4s", " ");
if (weekDay == 6) System.out.printf("%8s", " ");
for (i = 1; i <= mar; i++) {
System.out.printf("%4d", i);
if (weekDay == 0 && (i == 4 || i == 11 || i == 18 || i == 25)) System.out.println("\n");
if (weekDay == 1 && (i == 3 || i == 10 || i == 17 || i == 24)) System.out.println("\n");
if (weekDay == 2 && (i == 2 || i == 9 || i == 16 || i == 23 || i == 30)) System.out.println("\n");
if (weekDay == 3 && (i == 1 || i == 8 || i == 15 || i == 22 || i == 29)) System.out.println("\n");
if (weekDay == 4 && i % 7 == 0) System.out.println("\n");
if (weekDay == 5 && (i == 6 || i == 13 || i == 20 || i == 27)) System.out.println("\n");
if (weekDay == 6 && (i == 5 || i == 12 || i == 19 || i == 26)) System.out.println("\n");
}
}
答案 0 :(得分：1)
您的代码难以阅读，但您缺少System.out.printf（“％4d”，i）;在if（leapYear）下的块中。但是，你也应用闰年到三月......
另一种方法......
import java.util.Scanner;
public class StackOverflow_32900399 {
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
try
{
System.out.println("Enter a year");
int year = input.nextInt();
System.out.println("Enter first weekday of year e.g.: 0 for Sunday");
int weekDay = input.nextInt();
for (int month = 1; month <= 12; month++)
{
printMonthHeader(month, year);
weekDay = printDaysOfMonth(month, year, weekDay);
System.out.println("\n");
}
}
finally
{
input.close();
}
}
private static void printMonthHeader(int monthOfYear, int year)
{
String month = "";
switch (monthOfYear)
{
case 1 : month = "January"; break;
case 2 : month = "February"; break;
case 3 : month = "March"; break;
case 4 : month = "April"; break;
case 5 : month = "May"; break;
case 6 : month = "June"; break;
case 7 : month = "July"; break;
case 8 : month = "August"; break;
case 9 : month = "September"; break;
case 10 : month = "October"; break;
case 11 : month = "November"; break;
case 12 : month = "December"; break;
}
System.out.println(month + " " + year);
System.out.println("___________________________________");
System.out.println(" Sun Mon Tue Wed Thu Fri Sat ");
}
private static int printDaysOfMonth(int monthOfYear, int year, int startOn)
{
int daysInMonth = 0;
int currentDay = startOn;
switch(monthOfYear)
{
case 4 :
case 6 :
case 9 :
case 11 :
daysInMonth = 30;
break;
case 2:
daysInMonth = ((year % 4) == 0 ? 29 : 28);
break;
default:
daysInMonth = 31;
}
StringBuilder buff = new StringBuilder();
if (currentDay != 0)
{
buff.append(String.format("%1$"+(5*startOn)+ "s", ""));
}
for (int day = 1; day <= daysInMonth; day ++)
{
String padding = day > 9 ? " " : " ";
buff.append(padding + day + " ");
if (currentDay == 6)
{
buff.append("\n");
currentDay = 0;
}
else
{
currentDay++;
}
}
System.out.println(buff.toString());
System.out.println("___________________________________");
return currentDay;
}
}