Assignment help :)
Hi fellas, looking for some help in my progress with my assigment, program so far compiles fine its in 2 seperate files driver file and object file, im preety newb and the problem i cant solve is when i choose option 2 and enter an isbn number which is not found it doesnt do what its supposed to do, it gives me errors. Ignore the comments.
OBJECT FILE
/* Class details
* 1- Class Data members are defined
* 2- Two constructores
* 3_ service "CollectStudentRec()" [one record only]
* Note: nothing has being added to Step2Class to make Step3Class
*/
//importing JOptionPane class
import javax.swing.JOptionPane;
//menu options using switchStatement
public class Step3Class
{ // data memebers
static String HEADER = "ISBN Number Author BookTitlePrice\n"+
"===============================================================\n";
final static int MAX_BOOKS = 10;// Maximum number of students possible
static int books=0; // current number of students at any given time
String isbn ;// data member not an array
String author ;
String booktitle;
double price ;
// methods
//Constructor-1 with no args
public Step3Class()
{
isbn = "1-741";
author = "John Brown";
booktitle= "The Java Way";
price = 125.45;
}
//Constructor-2 with args
public Step3Class(String BId, String AName, String BName, double BCost)
{
isbn = BId;
author = AName;
booktitle= BName;
price = BCost;
}
// Class Services
public String CollectStudentRec()//Collect Rec-info
{String result ="";
result =isbn+""+
author+" "+
booktitle+""+
price+"\n";
return result;
}// Ednd of method CollectStudentRec()
public String getID() {
String id;
id = isbn;
return id;
}
}// end of 'class'
DRIVER FILE
/* 1_switchStatement
* 2_ A_ Creating one object & initialising the Student DB
*B_ Displaying the DB using "ref array"
* 3- Adding new student
*/
//importing JOptionPane class
import javax.swing.JOptionPane;
//menu options using switchStatement
public class Step3Driver
{
public static void main(String[] args)
{
// array of ref var of size 10 of type Step2Class
Step3Class[] arrBook= new Step3Class[10];
// creating the first object using default constructor
arrBook[0] = new Step3Class(); // default constructor
++Step3Class.books;// incrementing number of students
String menu="Enter a number to choose one of the following :\n"+
"(1) Process a new book\n"+
"(2) Search for a given ISBN number\n"+
"(3) Search for a given book title\n"+
"(4) Delete a given ISBN number\n"+
"(5) Calulate total number of books\n"+
"(6) Calculate total of all prices\n"+
"(7) Display current database\n"+
"(0) Quit(activity report)\n";
int option;// used to store users selection
String strOption;
do
{// Reading menu-input
strOption=JOptionPane.showInputDialog(null,menu,
"Please Select Option",JOptionPane.INFORMATION_MESSAGE );
option = Integer.parseInt(strOption);
// switch statement
switch(option){
// add a student to the database
// New code
case 1 :addBook(arrBook);
// End of new code
break;
// search for an ID number of a student
case 2:
String target = JOptionPane.showInputDialog(null,"Insert Book ISBN ","Search for Book", JOptionPane.INFORMATION_MESSAGE );
int answer = getisbnresult(target,arrBook);
if(answer==-1) // book is not found
JOptionPane.showMessageDialog(null,"*** ISBN number NOT FOUND ***\n"+
"The ISBN number "+ target +" does not exist.","Error",JOptionPane.INFORMATION_MESSAGE);
else
JOptionPane.showInputDialog(null,"menu",
"Please Select Option",JOptionPane.INFORMATION_MESSAGE );
break;
// find students name
case 3: JOptionPane.showMessageDialog(null,"InsertCode","Search for student name", JOptionPane.INFORMATION_MESSAGE );
break;
case 4: JOptionPane.showMessageDialog(null,"InsertCode","Delete a given ID rec", JOptionPane.INFORMATION_MESSAGE );
break;
// calculate total amount of students.
case 5: JOptionPane.showMessageDialog(null,"InsertCode","Total Amount of student", JOptionPane.INFORMATION_MESSAGE );
break;
// calculate total fees for students
case 6: JOptionPane.showMessageDialog(null,"InsertCode","Total Fees", JOptionPane.INFORMATION_MESSAGE );
break;
case 7: // to display current DB
//New cod//
//*******//
displayBooks(arrBook);
// End of new code//
// ***************//
break;
case 0: // to quit and print an activity report
JOptionPane.showMessageDialog(null,"InsertCode","Quit the program", JOptionPane.INFORMATION_MESSAGE );
break;
default:
JOptionPane.showMessageDialog(null,"Whoops !!!! Number must" +
" be between 0 & 7","Error in selection", JOptionPane.ERROR_MESSAGE );
} // end of switch
} while(option != 0); // end of loop
System.exit(0);// terminate the program
} // end of driver'main()'
// A static method calling a non static method for displaying Student DB
public static void displayBooks(Step3Class[] arrBook)
{String result;
result =Step3Class.HEADER;
for(int i=0;i<Step3Class.books;i++)
{
result +=arrBook.CollectStudentRec(); // "arrStudent" is the object
// "collectStudentRec()" is a class service
}
JOptionPane.showMessageDialog(null,result,"Current DataBase", JOptionPane.INFORMATION_MESSAGE );
}// Ednd of method display
public static void addBook(Step3Class[] arrBook)
{
String priceStr="", isbn,author,booktitle;
double price;
//checking if DB is full
if (Step3Class.books == arrBook.length)
{
JOptionPane.showMessageDialog(null,"Bookshelf is FULL !!","Error",
JOptionPane.ERROR_MESSAGE);
return;
}
// DB is not full. Reading a rec from user
isbn =JOptionPane.showInputDialog("What is the ISBN # ?");
author=JOptionPane.showInputDialog("What is the authors name ?");
booktitle=JOptionPane.showInputDialog("What is the book title ?");
priceStr=JOptionPane.showInputDialog("What is the price of the book ?");
price= Double.parseDouble(priceStr);
// creating an object using constructor2 with values read from the user
arrBook[Step3Class.books] = new Step3Class(isbn,author,booktitle,price);
// update student number
++Step3Class.books;
}
public static int getisbnresult(String target, Step3Class[] arrBook){
for (int i=0; i><=Step3Class.books; i++)
{
if (target.equals(arrBook.getID()))
return i;
}
return -1;
}
//***********************************************
}// end of 'class'
