Chapter 9, Problem 1E

Write a program that allows students to schedule appointments at either 1, 2, 3, 4, 5, or 6 o’clock pm. Use an array of six strings to store the names for the time slots. Write a loop that iterates as long as the array has a free space. Within a try block, allow the user to enter a time and a name. If the time is free, put the name in the array. If the time is not free, throw a TimeInUseException. If the time is not valid, throw an InvalidTimeException. Use a catch block for each different kind of exception.

Explanation of Solution

Creating “Main.java”:

• Import required packages.
• Declare the “Main” class.
  • Define the “main ()” method.
    • Create an object for the “Scanner” class.
    • Create a string array to store names.
    • Declare a variable “totalAppointments”.
    • Do the below steps till “totalAppointments” reaches 6 using “while” condition.
      • Get the name from the user.
      • Assign “false” to the Boolean variable “flag”.
      • Do until “flag” is false using “while” condition.
        • Inside “try” block,
        • • Get the appointment time from the user.
          • Check whether the time is less than 1 or greater than 6.
            • Throw an exception with a message.
          • Check whether “names [appointmentTime]” is not equal to null.
            • Throw an exception with a message.
          • Assign “name” to the index “names[appointmentTime]”.
          • Assign “true” to the variable “flag”.
          • Increment the variable “totalAppointments”.
        • Catch the exception “InvalidTimeException”.
        • • Print the message
        • Catch the exception “TimeInUseException”.
        • • Print the message.
        • Catch the exception “Exception”.
        • • Print the message.
    • Loop from 1 to 6 using “for” loop.
      • Print the makes and time for each person.

Creating “InvalidTimeException.java”:

• Define a class “InvalidTimeException” that extends “Exception”.
  • Define a parameterized constructor.
    • Call the parent class’s method using “super ()” by passing the message.

Creating “TimeInUseException.java”:

• Define a class “TimeInUseException” that extends “Exception”.
  • Define a parameterized constructor.
    • Call the parent class’s method using “super ()” by passing the message.

Program:

Main.java:

//Import required package

import java.util.*;

//Define the main class

public class Main

{

    //Define the main method

    public static void main(String[] args)

    {

        //Create an object for the scanner class

        Scanner sc = new Scanner(System.in);

        //Create a string array to store names

        String names[] = new String[7];

        //Declare a variable

        int totalAppointments = 0;

        //Do until the value reaches 6

        while(totalAppointments < 6)

        {

            //Get the name from the user

System.out.print("\nWhat is your name? ");

            String name = sc.next();

            //Declare a Boolean variable

            boolean flag = false;

            //Do until flag is false

            while(!flag)

            {

                //Try block

                try

                {

//Get the appointment time from the user

System.out.print("When would you like to make an appointment? ");

int appointmentTime = sc.nextInt();

//Check whether the appointment time is less than 1 or greater than 6

if(appointmentTime < 1 || appointmentTime > 6)

                        //Throw an exception

throw new InvalidTimeException("Time value not in range");

//Check if the appointment time is already fixed

if (names[appointmentTime] != null)

                        //Throw an exception

throw new TimeInUseException("appointment already made at that time");

//Save the name at the scheduled time index

names[appointmentTime] = name;

                    //Assign true

                    flag = true;

                    //Increment the variable

                    totalAppointments ++;

                }

                //Catch block

                catch (InvalidTimeException e)

                {

                    //print the message

System.out.println("Sorry, that is not a legal time");

                }

                //Catch block

                catch (TimeInUseException e)

                {

                    //print the message

System.out.println ("Sorry, that time is already in use");

                }

                //Catch block

                catch (Exception e)

                {

                    //print the message

System.out.println("Bad time format, should just be an integer");

// Use up the rest of the line

                    sc.nextLine();

                }

            }

        }

        //Print the statement

System.out.println("-----------------------------------\nScheduled Time\n\n");

        for(int i=1; i<=6; i++)

        {

//Print the names and the appointmentTime for each person

System.out.println("At " + i +"PM is " + names[i]);

        }

    }

}

InvalidTimeException.java:

//Define a class that throws Exception

public class InvalidTimeException extends Exception

{

    //Define a parameterized constructor

    public InvalidTimeException(String reason)

    {

//Call the parent class's method by passing the message

        super(reason);

    }

}

TimeInUseException.java:

//Define a class that throws Exception

public class TimeInUseException extends Exception

{

    //Define a parameterized constructor

    public TimeInUseException(String reason)

    {

//Call the parent class's method by passing the message

        super(reason);

    }

}

Sample Output

Output:

What is your name? Charles

When would you like to make an appointment? 6

What is your name? Adams

When would you like to make an appointment? 6

Sorry, that appointmentTime is already in use

When would you like to make an appointment? 5

What is your name? Bekkie

When would you like to make an appointment? 1

What is your name? David

When would you like to make an appointment? 4

What is your name? Sam

When would you like to make an appointment? 3

What is your name? Iris

When would you like to make an appointment? 2

-----------------------------------

Scheduled Time

At 1PM is Bekkie

At 2PM is Iris

At 3PM is Sam

At 4PM is David

At 5PM is Adams

At 6PM is Charles