finished exercise 28

Author: Jonathan-Birkey

src/com/github/jonathanbirkey/chapter05/Exercise28.java

@@ -0,0 +1,116 @@
+/**
+ * @author : Jonathan Birkey
+ * @mailto : [email protected]
+ * @created : 28Feb2024
+ *     <p>(Display the first days of each month) Write a program that prompts the user to enter the
+ *     year and first day of the year, then displays the first day of each month in the year. For
+ *     example, if the user entered the year 2013, and 2 for Tuesday, January 1, 2013, your program
+ *     should display the following output:
+ *     <p>January 1, 2013 is Tuesday
+ *     <p>...
+ *     <p>December 1, 2013 is Sunday
+ */
+package com.github.jonathanbirkey.chapter05;
+
+import java.util.Scanner;
+
+public class Exercise28 {
+  public static void main(String[] args) {
+    Scanner input = new Scanner(System.in);
+    System.out.print("Enter year: (e.g., 2012): ");
+    int year = input.nextInt();
+    System.out.print("Enter first day of year (0 - Saturday, 1 - Sunday, 2 - Monday, etc): ");
+    int firstDay = input.nextInt();
+    input.close();
+
+    int futureDay = firstDay;
+    int daysInMonth = 0;
+    String monthStr;
+
+    for (int month = 1; month <= 12; month++) {
+      if (month == 1
+          || month == 3
+          || month == 5
+          || month == 7
+          || month == 8
+          || month == 10
+          || month == 12) {
+        daysInMonth = 31;
+      } else if (month == 4 || month == 6 || month == 9 || month == 11) {
+        daysInMonth = 30;
+      } else {
+        if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
+          daysInMonth = 29;
+        } else {
+          daysInMonth = 28;
+        }
+      }
+      switch (month) {
+        case 1:
+          monthStr = "January";
+          break;
+        case 2:
+          monthStr = "Febuary";
+          break;
+        case 3:
+          monthStr = "March";
+          break;
+        case 4:
+          monthStr = "April";
+          break;
+        case 5:
+          monthStr = "May";
+          break;
+        case 6:
+          monthStr = "June";
+          break;
+        case 7:
+          monthStr = "July";
+          break;
+        case 8:
+          monthStr = "August";
+          break;
+        case 9:
+          monthStr = "September";
+          break;
+        case 10:
+          monthStr = "October";
+          break;
+        case 11:
+          monthStr = "November";
+          break;
+        case 12:
+          monthStr = "December";
+          break;
+        default:
+          monthStr = "Invalid";
+      }
+      switch (futureDay) {
+        case 0:
+          System.out.printf("%s 1, %d is Saturday\n", monthStr, year);
+          break;
+        case 1:
+          System.out.printf("%s 1, %d is Sunday\n", monthStr, year);
+          break;
+        case 2:
+          System.out.printf("%s 1, %d is Monday\n", monthStr, year);
+          break;
+        case 3:
+          System.out.printf("%s 1, %d is Tuesday\n", monthStr, year);
+          break;
+        case 4:
+          System.out.printf("%s 1, %d is Wednesday\n", monthStr, year);
+          break;
+        case 5:
+          System.out.printf("%s 1, %d is Thursday\n", monthStr, year);
+          break;
+        case 6:
+          System.out.printf("%s 1, %d is Friday\n", monthStr, year);
+          break;
+        default:
+          System.out.println("Invalid");
+      }
+      futureDay = (futureDay + daysInMonth) % 7;
+    }
+  }
+}