更新

Author: mthli

Part4/CalendarTest.java

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+import java.text.DateFormatSymbols;
+import java.util.*;
+
+public class CalendarTest {
+    public static void main(String[] args) {
+        GregorianCalendar d = new GregorianCalendar();
+
+        int today = d.get(Calendar.DAY_OF_MONTH);
+        int month = d.get(Calendar.MONTH);
+
+        d.set(Calendar.DAY_OF_MONTH, 1);
+
+        int weekday = d.get(Calendar.DAY_OF_WEEK);
+
+        int firstDayOfWeek = d.getFirstDayOfWeek();
+
+        int indent = 0;
+        while (weekday != firstDayOfWeek) {
+            indent++;
+            d.add(Calendar.DAY_OF_MONTH, -1);
+            weekday = d.get(Calendar.DAY_OF_WEEK);
+        }
+
+        String[] weekdayNames = new DateFormatSymbols().getShortWeekdays();
+        do {
+            System.out.printf("%4s", weekdayNames[weekday]);
+            d.add(Calendar.DAY_OF_MONTH, 1);
+            weekday = d.get(Calendar.DAY_OF_WEEK);
+        } while (weekday != firstDayOfWeek);
+        System.out.println();
+        for (int i = 1; i <= indent; i++) {
+            System.out.print("    ");
+        }
+        d.set(Calendar.DAY_OF_MONTH, 1);
+        do {
+            int day = d.get(Calendar.DAY_OF_MONTH);
+            System.out.printf("%3d", day);
+            if (day == today) {
+                System.out.print("*");
+            } else {
+                System.out.print(" ");
+            }
+            d.add(Calendar.DAY_OF_MONTH, 1);
+            weekday = d.get(Calendar.DAY_OF_WEEK);
+            if (weekday == firstDayOfWeek) {
+                System.out.println();
+            }
+        } while (d.get(Calendar.MONTH) == month);
+        if (weekday != firstDayOfWeek) {
+            System.out.println();
+        }
+    }
+}

Part4/ConstructorTest.java

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+import java.util.*;
+
+public class ConstructorTest {
+    public static void main(String[] args) {
+        Emplogee[] staff = new Emplogee[3];
+        staff[0] = new Emplogee("Harry", 40000);
+        staff[1] = new Emplogee(60000);
+        staff[2] = new Emplogee();
+
+        for (Emplogee e : staff) {
+            System.out.println(
+                    "name = " + e.getName() +
+                    ", id = " + e.getId() + 
+                    ", salary = " + e.getSalary()
+                    );
+        }
+    }
+}
+
+class Emplogee {
+    private static int nextId;
+
+    private int id;
+    private String name = "";
+    private double salary;
+
+    static {
+        Random generator = new Random();
+        nextId = generator.nextInt(10000);
+    }
+
+    {
+        id = nextId;
+        nextId++;
+    }
+
+    public Emplogee(String n, double s) {
+        name = n;
+        salary = s;
+    }
+
+    public Emplogee(double s) {
+        this("Emplogee #" + nextId, s);
+    }
+
+    public Emplogee() {
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public int getId() {
+        return id;
+    }
+}
+

Part4/EmployeeTest.java

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+import java.util.*;
+
+public class EmployeeTest {
+    public static void main(String[] args) {
+        Employee[] staff = new Employee[3];
+        staff[0] = new Employee("Calrl Cracker", 75000, 1987, 12, 15);
+        staff[1] = new Employee("Harry Hacker", 50000, 1989, 10, 1);
+        staff[2] = new Employee("Tony Tester", 40000, 1990, 3, 15);
+        
+        for (Employee e : staff) {
+            e.raiseSalary(5);
+        }
+
+        for (Employee e : staff) {
+            System.out.println(
+                    "name = " + e.getName() + 
+                    ", salary = " + e.getSalary() + 
+                    ", hireDay = " + e.getHireDay()
+                    );
+        }
+    }
+}
+
+class Employee {
+    private String name;
+    private double salary;
+    private Date hireDay;
+
+    public Employee(String n, double s, int year, int month, int day) {
+        name = n;
+        salary = s;
+        GregorianCalendar calendar = new GregorianCalendar(year, month - 1, day);
+        hireDay = calendar.getTime();
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public Date getHireDay() {
+        return hireDay;
+    }
+
+    public void raiseSalary(double byPercent) {
+        double raise = salary * byPercent / 100;
+        salary += raise;
+    }
+}
+

Part4/ParamTest.java

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+public class ParamTest {
+    public static void main(String[] args) {
+        System.out.println("Testing tripleValue:");
+        double percent = 10;
+        System.out.println("Before: percent = " + percent);
+        tripleValue(percent);
+        System.out.println("After: percent = " + percent);
+
+        System.out.println("\nTesting tripleSalary:");
+        Employee harry = new Employee("Harrt", 50000);
+        System.out.println("Before: salary = " + harry.getSalary());
+        tripleSalary(harry);
+        System.out.println("After: salary = " + harry.getSalary());
+
+        System.out.println("\nTesting swap:");
+        Employee a = new Employee("Alice", 70000);
+        Employee b = new Employee("Bob", 60000);
+        System.out.println("Before: a = " + a.getName());
+        System.out.println("Before: b = " + b.getName());
+        swap(a, b);
+        System.out.println("After: a = " + a.getName());
+        System.out.println("After: b = " + b.getName());
+    }
+
+    public static void tripleValue(double x) {
+        x = 3 * x;
+        System.out.println("End of method: x = " + x);
+    }
+
+    public static void tripleSalary(Employee x) {
+        x.raiseSalary(200);
+        System.out.println("End of method: salary = " + x.getSalary());
+    }
+
+    public static void swap(Employee x, Employee y) {
+        Employee temp = x;
+        x = y;
+        y = temp;
+        System.out.println("End of method: x = " + x.getName());
+        System.out.println("End of method: y = " + y.getName());
+    }
+}
+
+class Employee {
+    private String name;
+    private double salary;
+
+    public Employee(String n, double s) {
+        name = n;
+        salary = s;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public void raiseSalary(double byPercent) {
+        double raise = salary * byPercent / 100;
+        salary += raise;
+    }
+}
+

Part4/StaticTest.java

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+public class StaticTest {
+    public static void main(String[] args) {
+        Employee[] staff = new Employee[3];
+        
+        staff[0] = new Employee("Tom", 40000);
+        staff[1] = new Employee("Dick", 60000);
+        staff[2] = new Employee("Harry", 65000);
+
+        for (Employee e : staff) {
+            e.setId();
+            System.out.println(
+                    "name = " + e.getName() +
+                    ", id = " + e.getID() +
+                    ", salary = " + e.getSalary()
+                    );
+        }
+        int n = Employee.getNextId();
+        System.out.println("Next available id = " + n);
+    }
+}
+
+class Employee {
+    private static int nextId = 1;
+
+
+    private String name;
+    private double salary;
+    private int id;
+
+    public Employee(String n, double s) {
+        name = n;
+        salary = s;
+        id = 0;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public int getID() {
+        return id;
+    }
+
+    public void setId() {
+        id = nextId;
+        nextId++;
+    }
+
+    public static int getNextId() {
+        return nextId;
+    }
+
+    public static void main(String[] args) {
+        Employee e = new Employee("Harry", 50000);
+        System.out.println(e.getName() + " " + e.getSalary());
+    }
+}