(Java beginner problems) Why doesn't this code work?

(full code below) I just passed a lab for a class where we needed to create a class that describes a specific book. I couldn't figure out how to do two things. 1. If someone enters a value less than zero for "pages" or "suggested by RetailPrice", the value must be set to zero. In this code, the value is 0 even if the value is positive. IN:

if ( pages <= 0 )
    {
        pages = 0;
    }

      

        
        
        
      

    

if I set the second "0" to a different number, say:

if ( pages <= 0 )
    {
        pages = 1;
    }

      

        
        
        
      

    

Then the value for what you enter for "pages" will be 1. But shouldn't it be 1 ONLY if the value you entered is negative? I don't understand what I am doing wrong.

The second thing I couldn't figure out is at the bottom of the code, we needed to display all the information. My teacher wanted us to show if the paperback was “yes” or “no” instead of “true” or “false”. How should I do it? I tried to put the if / else statement like this: System.out.println ("Paperback:" + if (paperback = true) {Yes} if (paperback = false) {no};)

Doesn't work, I can't understand. See all the code below.

public class Book {
    // Instance variables
    private String title;
    private String author;
    private int isbn;
    private int pages;
    private boolean paperback;
    private int suggestedRetailPrice;

    /**
     * Default contructor
     */
    public Book() {
        title = "";
        author = "";
        isbn = 0;
        pages = 0;
        paperback = false;
        suggestedRetailPrice = 0;
    }

    /**
     * book information
     */
    public Book(String whatIsTitle, String whoIsAuthor, int isbnCode,
            int numberOfPages, boolean isItPaperback,
            int theSuggestedRetailPrice) {
        title = whatIsTitle;
        author = whoIsAuthor;
        isbn = isbnCode;
        if (pages <= 0) {
            pages = 0;
        } else {
            pages = numberOfPages;
        }
        paperback = isItPaperback;
        if (suggestedRetailPrice <= 0) {
            suggestedRetailPrice = 0;
        } else {
            suggestedRetailPrice = theSuggestedRetailPrice;
        }
    }

    /**
     * @return title
     */
    public String getTitle() {
        return title;
    }

    /**
     * @return author
     */
    public String getAuthor() {
        return author;
    }

    /**
     * @return isbn
     */
    public int getIsbn() {
        return isbn;
    }

    /**
     * @return pages
     */
    public int getPages() {
        return pages;
    }

    /**
     * @return paperback
     */
    public boolean getPaperback() {
        return paperback;
    }

    /**
     * @return suggestedRetailPrice
     */
    public int getSuggestedRetailPrice() {
        return suggestedRetailPrice;
    }

    /**
     * title
     */
    public void setTitle(String whatIsTitle) {
        title = whatIsTitle;
    }

    /**
     * author
     */
    public void setAuthor(String whoIsAuthor) {
        author = whoIsAuthor;
    }

    /**
     * isbn code
     */
    public void setIsbn(int isbnCode) {
        isbn = isbnCode;
    }

    /**
     * number of pages
     */
    public void setPages(int numberOfPages) {
        if (pages <= 0) {
            pages = 0;
        } else {
            pages = numberOfPages;
        }
    }

    /**
     * is it paperback
     */
    public void setPaperback(boolean isItPaperback) {
        paperback = isItPaperback;
    }

    /**
     * suggested retail price
     */
    public void setSuggestedRetailPrice(int theSuggestedRetailPrice) {
        if (suggestedRetailPrice <= 0) {
            suggestedRetailPrice = 0;
        } else {
            suggestedRetailPrice = theSuggestedRetailPrice;
        }
    }

    /**
     * displays information
     */
    public void displayBook() {
        System.out.println("Title : " + title);
        System.out.println("Author : " + author);
        System.out.println("ISBN : " + isbn);
        System.out.println("Pages : " + pages);
        System.out.println("Paperback : " + paperback);
        System.out.println("Suggested price : " + suggestedRetailPrice);
    }
}