Question

我在两种方法中遇到错误，public int getBookIndex和public boolean updateTitle。

/ d / 1r4XAhOC0VvWfaxnPZUFyiSGdk2gpFs2mZoTkJ6CJnGk /编辑？USP =共享

 public class Library {

    private String[] titles ;

    private int[] nbPages;

    private int nb;

    private String[] author;

    public Library(int total_books) {

        nb = total_books;
        titles = new String[nb];
        nbPages = new int[nb];
        author = new String[nb];
    }


    public void setDate(String tit, int nbP, String au) {

        for(int x=0; x<=nb; x++){

            titles[x] = tit;
            author[x] = au;
            nbPages[x] = nbP;
        }
    }

    public void DisplayAll() {

        for(int x=0;x<=nb;x++) {

            System.out.println(titles[x] + nbPages[x] + author[x]);
        }
    }


    public void displayBook(String title){

        for(int x=0;x<=nb;x++)

            if(title == titles[x]){

                System.out.println(titles[x] + author[x] + nbPages[x]);

                break;
            }
        }


    public void displayBook(int number){

        System.out.println(titles[number] + author[number]);

    }



    public void displayAuthorBooks(String auth) {

        for(int x=0;x<=nb;x++){

            if(auth == author[x])
                System.out.print(titles[x]+nbPages[x]+author[x]);
        }
    }


    public void displayNumberOfBooksAuthor(String auth){

        int count = 0;

        for(int x=0;x<=nb;x++){

            if(auth == author[x])
                count++;

        }

        System.out.println("the books for this author is :" + count);

    }

    public boolean addBook(String titl, int nbp) {

        nb++;

        titles[nb] = titl;


        nbPages[nb] = nbp;

        return true ;
    }

    public boolean deleteBook(int index){

        if(index <= nb) {
            nb--;
            return true;
        }
        else 
            return false ;

    }


    public boolean updateTitle(int index,String tit) {

        if((titles[index] == tit) == true)
            return true;
        else 
            return false;
    }


    public int getBookIndex(String find_tit){

        for(int x=0;x<=nb;x++){

            if(titles[x] == find_tit){

                return (x++);

                break;
            }
            else
                return(-1);
        }
    }


    public boolean updateTitle(String old_titl,String new_titl) {

        for(int x=0;x<=nb;x++){

            if(titles[x] == old_titl) {

                titles[x] = new_titl;
                return true;
                break;
            }
            else 
                return false;

        }
    }
}

Answer 1

删除你的break语句（你的其他条件也是错误的） - 就像这样

public int getBookIndex(String find_tit) {
  for (int x = 0; x < nb; x++) { // not sure, but probably not <=
    if (titles[x].equals(find_tit)) { // not ==
       return x; // probably not x+1.
    }
  }
  return (-1);
}

public boolean updateTitle(String old_titl,
    String new_titl) {
  for (int x = 0; x < nb; x++) { // not sure, but probably not <=
    if (titles[x].equals(old_titl)) { // not ==
      titles[x] = new_titl;
      return true;
    }
  }
  return false;
}

麻烦的java中的书籍数组

1 个答案: