CODEWITHSUNDEEP
javaobjectconstructorcompiler-errors
user3084192
user3084192

Reputation: 369

Cannot find constructor even though parameters are correct

I've been trying to figure out the reason of this error but I'couldn't :( And I need your help to solve it :)

1.I checked the actual parameter list to make sure it matches the formal parameter list and it did.

2.the constructor Book() with no parameter list worked just fine when I replaced it with the current.

Error:

Library.java:83: cannot find symbol
symbol  : constructor Book(int,java.lang.String,java.lang.String,java.lang.String,java.lang.String)
location: class Book
         libraryBooks[100-Book.totalNum] = new Book (ISBN,Author,publishedYear,title,genre);
                                           ^
1 error

Class Book:

      public class Book {
    private int ISBN;
    private String author;
    private String publicationYear;
    private String title;
    private String genre;
    public static int totalNum=1;
    private String refCode;

    public void Book(int isbn,String auth,String year,String Title,String Genre){
    ISBN=isbn;
    author=auth;
    publicationYear=year;
    title=Title;
    genre=Genre;
    }

    public void Book(){
    ISBN=1234;
    author="-";
    publicationYear="2012";
    title="-";
    genre="-";
    }

public static boolean verifyISBN(int isbn1){
    int[] n=new int [4];
    int isbn=isbn1;
    n[3]=isbn%10;
    for(int i=2;i>=0;i--){
    isbn/=10;
    n[i]=isbn%10;}
    if (((n[0]*3+n[1]*2+n[2]*1)%4)==n[3])
    return true;
    return false; 
}
    }

Class Library:

import java.util.*;
public class Library {
   private static Scanner console=new Scanner(System.in);
   private static Book [] libraryBooks=new Book  [100];

   public static void main (String[]args){

                  System.out.println("Enter the book\'s ISBN");
                  int ISBN=console.nextInt();
                  System.out.println("Enter the book\'s author name");
                  String author=console.next();
                  System.out.println("Enter the book\'s publish year");
                  String publicationYear=console.next();
                  System.out.println("Enter the book\'s title");
                  String title=console.next();
                  System.out.println("Enter the book\'s genre");
                  String genre=console.next();
                  if(addBook(ISBN,author,publicationYear,title,genre))
                     System.out.println("The book was successfully added to your library");
                  else
                     System.out.println("The book sasn't successfully added to your library");

}
   public static boolean addBook(int ISBN,String Author,String publishedYear,String title, String genre){
      if (Book.verifyISBN(ISBN)&&(findBook(ISBN)!=-1)){
         libraryBooks[100-Book.totalNum] = new Book (ISBN,Author,publishedYear,title,genre);
         Book.totalNum++;
         return true;}
      return false;
   }

   public static int findBook(int ISBN){
      for (int i=99;i>=(100-Book.totalNum);i--)
         if(libraryBooks[i].getISBN()==ISBN)
            return i;

      return -1;
   }}

Please help me :( !

Upvotes: 0

Views: 1140

Answers (2)

Pankaj Goyal
Pankaj Goyal

Reputation: 980

Here In this program you makes a very small mistake . You forgot one important property of constructor that is constructor does not have a return type. here you are giving return type as void but internally its automatically returns current class object . I hope now this concept will be more clear for you.

Upvotes: 1

rgettman
rgettman

Reputation: 178263

This line isn't a constructor because of the void keyword (constructors don't have return types). You've created a method that returns void.

public void Book(int isbn,String auth,String year,String Title,String Genre){

Remove void:

public Book(int isbn,String auth,String year,String Title,String Genre){

You'll need to do likewise with your other Book "method":

public Book(){

You didn't define any actual constructors, so Java implicitly included a default constructor that takes no arguments (and does nothing). That is why calling it with no parameters didn't have an error.

Upvotes: 4

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