Thread: Keeping track of found objects in array and smallest value

Hello I am trying to devise some code to store the index values of where I have found a book title and key code (which will be ISBN) in an array, I am stuck at here

for (int k = 0; k < bkArr2.length; k++)
    {
	if (bkArr2[k].getTitle().equals(titl) && bkArr2[k].getISBN() == ISB)
         {
	System.out.println("Index Information At Index Arr[" + k + "]: " +  bkArr2[k].toString());
	//bkArr2[k].getPrice();
          }
     }

if there equal I print a line saying I found it but also want to store all the values found, there could be more then 1. Should I make a second array and store the values there?

how do I keep track of the values stored and then find the smallest of those values using my above code and my other class (down below), is the question.

class Book {
//Attributes of Book
 
public String title;
public long ISBN;
public double price;
 
//Constructor of Book
 
public Book()
{
System.out.println("Creating Book.....");
	title = "abc";
	price = 25;
	ISBN = 1234;
}
 
public Book(String ti, double pr, long ib)
{
	title = ti;
	price = pr;
	ISBN = ib;
}
 
//Methods of book
public Book(Book bk)
{ //Copy Constructor
System.out.println("Creating object with copy constructor.....");
	title = bk.title;
	price = bk.price;
	ISBN = bk.ISBN;
}
 
public void setPrice(double pr)
{//sets the price of the book
	price = pr;
}
public double getPrice()
{//gets the price of the book
	return price;
}
 
public void setTitle(String ti)
{//sets the title of the book
	title = ti;
}
 
public String getTitle()
{//gets the title of the book
	return title;
}
 
public void setISBN(long num)
{//sets the ISBN of the book
	ISBN = num;
}
 
public long getISBN()
{//gets the ISBN of the book
return ISBN;
}
 
public String toString()
{//returns book values
	System.out.println("The book title is " + title + ", the ISBN number is " + ISBN + " and the price is " + price +"$.\n");
	return (title + " " + ISBN + " " + price);
}
}

thanks for stating the obvious, I was hoping for an example, but I guess you think I am being lazy and want you to spit out the answer...WRONG! I am deeply confused and need help, heres my attempt, please let me know if I am on the right track, its hard to wrap my head around thats why i ask for help!

 for (int k = 0; k < bkArr2.length; k++)
		    {
		    	if (bkArr2[k].getTitle().equals(titl) && bkArr2[k].getISBN() == ISB)
		    	{
		    System.out.println("Index Information At Index Arr[" + k + "]: " +  bkArr2[k].toString());
		    		k = valueFound[i];
		    		i++;
		    	}
		    }
		    int minValue = 100000;
		    for (j = 0; j < valueFound.length; j++)
		    {
		    	if (bkArr2[valueFound[j]].getPrice() < minValue)
		    	{
		    		minValue = valueFound[j];
 
		    	}
 
		    }

the first for loop goes through my list checking for books with the same price and ISBN # and then stores where they are located in that array, into a separate array (i want to change the price after). The second for loop is looking for the smallest price amongst those found with the same title and ISBN. All books that were found with
the same title and the same ISBN will then be changed to have the smallest price that any of them has.

"set smallest value variable to the first element in the list
begin loop starting at the second element in the list"

whats wrong with the way I have it above? If I am checking all the values of the list, the first one will be the smallest and then so on I continue checking to see if the other elements are smaller than the first one and so on.


heres code with comments, your right I think it will be easier this way to explain what I mean:

//Go through my array check to see if ISBN and TITLE are equal
for (int k = 0; k < bkArr2.length; k++)
		    {
		    	if (bkArr2[k].getTitle().equals(titl) && bkArr2[k].getISBN() == ISB)
		    	{//if equal, display where in the index they are found, and store that value for later
		    		System.out.println("Index Information At Index Arr[" + k + "]: " +  bkArr2[k].toString());
		    		k = valueFound[i];
		    		i++;
		    	}
		    } //check to see which is the smallest value because I want to change all of the found books with the same
                      //ISBN and TITLE to the smallest price amongst them
 
                      int minValue = 100000; //initialize a value that will be to big for it to be minvalue
		    for (j = 0; j < valueFound.length; j++) //go through the array of values found that have same titile/isbn
		    {
 
                       	if (bkArr2[valueFound[j]].getPrice() < minValue) //get price at that array value
		    	{
		    		minValue = valueFound[j]; //set it to the min so anything that comes after that is smaller will replace it
 
		    	}
		    }
		    //Modify all books found  To Smallest Price amongst them
		    for (int p = 0; p < valueFound.length; p++)
 
                   {
		    	bkArr2[valueFound[p]].setPrice(minValue); //set the prices of all those values found to the smallest price
		    	System.out.println("Price of Book at index "+  ); // and then display them, incomplete!
		    }

I just ran it and got:

Please enter a book title:
ho
Please enter a ISBN number:
1001
The book title is ho, the ISBN number is 1001 and the price is 70.0$.

Index Information At Index Arr[0]: ho 1001 70.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
The book title is ho, the ISBN number is 1001 and the price is 40.0$.

Index Information At Index Arr[1]: ho 1001 40.0
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 10
at ModifyBooks.main(ModifyBooks.java:58)

so not what I wanted

System.out.println("Index Information At Index Arr[" + k + "]: " +  bkArr2[k].toString());
		    		k = valueFound[i]; // <--- something wrong here
		    		i++;

By looking at my code is that what you recommend I should do?

Yes I am trying to change the size of the ray and make it equal to my count which would have been the amount of times where my title and ISBN are the same. That way only the ones that are found will be displayed and also the prices of those will be changed instead of displaying every element and changing every element.

ok I will try now, thanks, thought there might have been another way/method

I dont know what array list is, havent learned that yet, also if I were to move it to another array, say ar1 = ar2 wouldn't they just be the same size and the same outcome would happen?