/*

private static int Textbook = 0; //0 initial value

private static final Scanner input = new Scanner(System.in); //Scanner obj

private static final String SGAP = " ";

private static int r = 0; //i.v./r var must be here to add Book after disply method

private static final Book[] book = new Book[20];

public static void main(String[] args)throws IOException{

//Book[] book = new Book[20];

menu(); //prompt the user to select a choice from a menu

}

public static String menu()throws IOException{

String one = "1.Enter books information", //prompts Numbers

two = "2.Display books information",

three = "3.Search by book's title",

four = "4.Discount 15% from books prices",

five = "5.Exit",

gap = " ",

l1 = gap+"♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥♥\n", //menu lines

l2 = gap+"♥♥♥♥♥♥♥♥♥♥♥♥♥ MENU ♥♥♥♥♥♥♥♥♥♥♥♥♥\n",

l3 = gap+"♥♥♥♥ "+one+" ♥♥♥♥\n",

l4 = gap+"♥♥♥♥ "+two+" ♥♥♥♥\n",

l5 = gap+"♥♥♥♥ "+three+" ♥♥♥♥\n",

l6 = gap+"♥♥♥♥ "+four+" ♥♥♥♥\n",

l7 = gap+"♥♥♥♥ "+five+gap+" ♥♥♥♥\n";

System.out.print(l1+l2+l1+l3+l4+l5+l6+l7+l1+"\n\n"); //prints whole menu

System.out.print("Your choice:");

String choiceNum = input.nextLine(); //String,to let the user to enter any thing without Exceptions

while(!"5".equals(choiceNum)){ //like choiceNum != 5

switch(choiceNum){

case "1":

setBooks(book);

break;

case "2":

displayBooks();

break;

case "3":

findBooks();

break;

case "4":

discountPrice();

break;

default:

System.out.print("Invalid choice!"+"\n\nYour choice:");

choiceNum = input.nextLine();

continue;

}

System.out.print("\n"+l1+l2+l1+l3+l4+l5+l6+l7+l1+"\nYour choice:");

choiceNum = input.nextLine();

}

return choiceNum;

} //end menu method

//Book[] 'Book'here is dataType ,which is our class Book.java

public static int setBooks(Book[] book)throws IOException{ //prompt 1

String sPrice,

PubYear;

String Add = "y"; //initil value cuz when user input pt1 that's means he want to add book!

while("y".equals(Add) || "Y".equals(Add)){

if(Textbook < 20){

if( r <= book.length){

book[r] = new Book();

Textbook = 1+Textbook;

int t = 0, //t,y to know if we reached the valid value,if t,y = 1 ok take it and move

y = 0;

System.out.printf("\nTextbook #%d %n",Textbook);

System.out.print("Title: ");

book[r].setbTitle(input.nextLine());

System.out.print("Price: ");

sPrice = input.next();

while(t == 0) { //sPrice,PubYear Strings to let user input anything then

try{ //we'll try to convert them to numerical value if we could't

book[r].setbPrice(Double.valueOf(sPrice)); //that's means user input invalid value(St),then let it input again

if( book[r].getbPrice() >= 0){ //if we could convert them to numerical,then check more conditions

t = t + 1;

}

else{

System.out.print("Price Again : ");

sPrice = input.next();

}

}catch(NumberFormatException e){

System.out.print("Price Again : ");

sPrice = input.next();

}}

System.out.print("Publication year: ");

PubYear = input.next();

while(y == 0) {

try{

book[r].setbPubYear(Integer.valueOf(PubYear));

if(book[r].getbPubYear() > 0 && book[r].getbPubYear() <= 2019){

y = y + 1;

}

else{

System.out.print("Publication year Again : ");

PubYear = input.next();

}

}catch(NumberFormatException e){

System.out.print("Publication year Again : ");

PubYear = input.next();

}}

input.nextLine(); // This line you have to add (It consumes the \n character)

r = 1+r; //r here to let r start from 0, index of the array start from 0,and updated after adding

System.out.print("Add another textbook (y/n)? ");

Add = input.nextLine();

while(!"n".equals(Add) && !"N".equals(Add) && !"y".equals(Add) && !"Y".equals(Add)){ //if user input invalid value

System.out.print("Add another textbook (Y/N)? "); //prompt it until y/n

Add = input.nextLine();

}}}else{

Add = "n"; //if books > 20 change Add to "n" to skip what user want (Add=y he want to Add book)

System.out.print("You can't add more than 20 books!\n\n");

}

}

return Textbook; //Num of Books entered

} //end setBook method

public static void displayBooks(){ //prompt 2

switch(Textbook){

case(0):

System.out.print("There is no books info to display!! \n\n");

break;

default:

int i = 1;

int b = 0; //means first book

while(i <= Textbook){

int Textbook2 = Textbook-(Textbook-i);

System.out.printf("\nTextbook #%d\n",Textbook2);

System.out.printf("Title: %s %S",book[b].getbTitle(),SGAP);

System.out.printf("Price: £%.1f %S",book[b].getbPrice(),SGAP);

System.out.printf("Publication year: %S \n\n",book[b].getbPubYear());

i = i + 1;

b = b + 1; //to go to the next Index of The book Array

}

}

}//end displayBooks method

public static void findBooks(){ //prompt 3

switch(Textbook){

case 0:

System.out.print("No books have been added to search in! \n\n");

break;

default:

System.out.println("\nFind the first THREE books with the same title:");

String fBook = input.nextLine(),

sfBook = fBook.toLowerCase(); //search by LC to find all possible Titles,what ever they(LC,UC,mixed)

int abook = 0, //to check if we found a book

b = 0; //to start from Index 0

for(int i = 1; i <= Textbook; i++){

boolean check = sfBook.equals(book[b].getbTitle().toLowerCase()); //make all Titles LC to match sfBook

if(check == true){

if(abook < 3){ //to print first 3

System.out.printf("Title: %s %S",book[b].getbTitle(),SGAP);

System.out.printf("Price: £%.1f %S",book[b].getbPrice(),SGAP);

System.out.printf("Publication year: %S \n\n",book[b].getbPubYear());

abook = abook + 1;

b = b + 1;

}}

else if(check == false){ b = b + 1;}

}

if(abook == 0) {

System.out.printf("There is no books with title \"%s\"\n\n",fBook);}

}

} //end findBooks method

public static void discountPrice(){ //prompt 4

switch(Textbook){

case(0):

System.out.print("No books have been added to discount!! \n\n");

break;

default:

int i = 1;

int b = 0; //to start from Index 0

while(i <= Textbook){

book[b].setbPrice(book[b].getbPrice() - (book[b].getbPrice()*0.15));

b = b + 1; //to go to the next Index of The book Array

i = i + 1;

} System.out.println("Discount is done! ");

}

} //end discountPrice method