Write a complete address book maintenance application. The user of the program has three options: add new person, delete a person and modify the data of a person.
You have to decide how to allow the user to enter the values for a new person, and the other options.
You must use files in order to save and read the data.

Use the AddressBook class provided below.

the address book class
/*
Introduction to OOP with Java 4th Ed, McGraw-Hill

Wu/Otani

Chapter 10 Sample Program: Address Book Maintenance

File: AddressBook.java
*/

/**
* This class is designed to manage an address book that contains
* Person objects. The user can specify the size of the address book
* when it is created. If no size is specified, then the default size
* is set to 25 Person objects.
*
* @author Dr. Caffeine
*
*/
class AddressBook { //Step 4: Implement the delete method


//--------------------------------
// Data Members
//--------------------------------

/**
* Default size of the array
*/
private static final int DEFAULT_SIZE = 25;

/**
* Constant for signaling an unsuccessful search
*/
private static final int NOT_FOUND = -1;

/**
* The array of Person objects
*/
private Person[] entry;

/**
* The number of elements in the <code>entry</code> array,
* which is also the position to add the next Person object
*/
private int count;

//--------------------------------
// Constructors
//--------------------------------

/**
* Default constructor.
* Creates an address book of size 25.
*/
public AddressBook( ) {
this( DEFAULT_SIZE );
}


/**
* Creates an address book with the designated size.
*
* @param size the size of this address book.
*/
public AddressBook( int size ){
if (size <= 0 ) {
throw new IllegalArgumentException("Size must be positive.";
}

entry = new Person[size];

//System.out.println("Array of "+ size + " is created."; //TEMP
}


//-------------------------------------------------
// Public Methods:
//
// void add ( Person )
// void delete ( String )
// Person search ( String )
//
//------------------------------------------------

/**
* Adds a new Person to this address book.
* If the overflow occurs, the array size
* is increased by 50 percent.
*
* @param newPerson a new Person object to add
*/
public void add( Person newPerson ) {

assert count >= 0 && count <= entry.length;

if (count == entry.length) { //no more space left,
enlarge( ); //create a new larger array
}

//at this point, entry refers to a new larger array
entry[count] = newPerson;
count++;
}


/**
* Deletes the Person whose name is 'searchName'.
*
* @param searchName the name of a Person to delete
*
* @return true if removed successfully; false otherwise
*/
public boolean delete( String searchName )
{
boolean status;
int loc;

loc = findIndex( searchName );

if (loc == NOT_FOUND) {
status = false;
} else { //found, pack the hole

entry[loc] = entry[count-1];

status = true;
count--; //decrement count,
//since we now have one less element
assert count >= 0 && count <= entry.length;
}

return status;
}

/**
* Searches this address book for a Person
* whose name is <code>searchName</code>.
*
* @param searchName the name to search
*
* @return a Person object if found; otherwise null
*/
public Person search( String searchName ) {
Person foundPerson;
int loc = 0;

while ( loc < count &&
!searchName.equals( entry[loc].getName() ) ) {
loc++;
}

if (loc == count) {

foundPerson = null;
} else {

foundPerson = entry[loc];
}

return foundPerson;
}

//-------------------------------------------------
// Private Methods:
//
// void enlarge ( )
//
//------------------------------------------------

/**
* Enlarges the size of <code>entry</code> array to
* eliminate the overflow condition. The new array
* is 50 percent larger than the current array.
*/
private void enlarge( ) {
//create a new array whose size is 150% of
//the current array
int newLength = (int) (1.5 * entry.length);
Person[] temp = new Person[newLength];

//now copy the data to the new array
for (int i = 0; i < entry.length; i++) {
temp[i] = entry[i];
}

//finally set the variable entry to point to the new array
entry = temp;

System.out.println("Inside the method enlarge"; //TEMP
System.out.println("Size of a new array: " + entry.length); //TEMP
}

/**
* Finds the index in the array where <code>searchName</code>
* is the name of a person to locate.
*
* @param searchName the name of person to find
*
* @return the index of the found Person in the array; NOT_FOUND
* if the searched person is not found
*/
private int findIndex( String searchName ) {
int loc = 0;

while ( loc < count &&
!searchName.equals( entry[loc].getName() ) ) {
loc++;
}

if (loc == count) {

loc = NOT_FOUND;
}

return loc;
}
}

i really appereciate the help mane but the teach is askin for like an address book maintenance application  the adress book class already exists the app is just to update the adress book i.e add new person, delete a person and modify the data of a person he doesnt want the person class its alredy in the adress book code and dude specified that we must use files to save and read the data . will appreciate the help thnxs again

ay mane thnx for the help ill clean up the rest