Notes

package com.codington.module8;

/** * CheckEventPass is about checking the number of tickets assigned ticket ID's. * Topic: Java Error Handling and Assertions. */ public class CheckPassEvent { public static void main(String[] args) {

// variable declaration. int noOfChildren; int noOfAdults; int noOfTickets; int[] ticketID; int avgVisitor; int noOfDays = 0; /* * Initializing the following variables: a. number of children b. number * of adults c. number of tickets with the sum of number of children and * number of adults. */ noOfChildren = 2; noOfAdults = 6; noOfTickets = noOfChildren + noOfAdults;

// Initialize the array with number of tickets as the size.

ticketID = new int[noOfTickets]; //Note: Try changing value of "ticketID" index from [noOfTickets] to [noOfTickets-1] and see the output. //comment above line and uncomment below line in second run to check the output //ticketID = new int[noOfTickets-1];

// Try..Catch..Finally Demonstration try { System.out.println("Access element of ticket id := " + ticketID[noOfTickets - 1]); avgVisitor = noOfTickets / noOfDays; } catch (ArithmeticException | ArrayIndexOutOfBoundsException e) { System.out.println("Exception thrown :" + e);

} finally { System.out.println("Executing the finally block."); noOfDays = 2; avgVisitor = noOfTickets / noOfDays; System.out.println("Average visitor per day: " + avgVisitor);

}

int passID = 0;

/* * Iterate for loop starting zero to 'noOfTickets-1' so the last element * of the array doesn't get assigned a passID which will trigger the * assertion exception. */ for (int i = 0; i < noOfTickets - 1; i++) { // Generate ticket ID's and populate ticket ID array. passID = i + 1; ticketID[i] = passID; }

// Verify all the tickets issued assigned with ticket ID's using assert. int index = 0; System.out.println("Verifying tickets assigned with ticket ID's"); do { // If ticket id array value is equal to zero, print 'Mismatch in // issuance of ticket ID's' to the console as an assertion error assert (ticketID[index] != 0) : "Mismatch in issuance of ticket ID's"; System.out.println("Tickedt ID = " + ticketID[index]); index++; } while (index < ticketID.length);

// If assertion error occurs, this line will not be printed to the // console after exiting do..while loop.

System.out.println( "Ticket ID's are assigned to total number of tickets issued.");

} }