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Thread: PLEASE HELP WITH JAVA ARRAYLISTS! Thanks.

  1. #1
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    Question PLEASE HELP WITH JAVA ARRAYLISTS! Thanks.

    Here is the assignment:

    Write a program that does the following things.
    1. In main, create an ArrayList of the names in our class (Strings are objects)
    If you are using Scanner with a name with a space use nextLine()

    2. Use the size method to print out the size of the ArrayList

    3. Test all of the following methods that you will write.

    4. Write a method printList() to print out the list numbered vertically as seen at left.
    public static void printList(ArrayList<String> x)

    5. Write a method to delete all names that start with a given character
    public static void removeCh(ArrayList<String> x, char ch)
    **Be careful of duplicates***

    6. Write a method to add all the elements in a String array to the ArrayList
    public static void addArray(ArrayList<String> x, String[]names)

    7. Write a method to replace a given name with another name
    public static void replaceName(ArrayList<String> x, String oldOne,
    String newOne)

    8. Write a method to remove duplicates
    public static void removeDup(ArrayList<String> x)


    __________________________________________________ __________________________________

    This is the code I have so far:

    import java.util.ArrayList;

    public class Students
    public static void main(String[] args)
    {
    ArrayList<Students> names = new ArrayList();
    names.add("y");
    names.add("w");
    names.add("f");
    names.add("v");
    names.add("d");
    names.add("r");
    names.add("u");
    names.add("t");
    names.add("i");
    names.add("o");
    names.add("n");

    public static void printList(ArrayList<String> st)
    {
    for(int v=0; v<st.size(); v++) {
    System.out.println(v + st.get(v));
    }
    }

    public static void removeCh(ArrayList<String> st, char hh)
    {
    for(int g=0; g<st.size(); g++)
    {
    if(st.get(g).charAt(0) == hh)
    st.remove(g);
    g--;
    }
    }

    public static void addArray(ArrayList<String> st, String[]names)
    {
    for (int r=0; r<names.length; r++)
    {
    st.add(names[r]);
    }
    }

    public static void replaceName(ArrayList<String> st, String oldOne,String newOne)
    {
    for (int e=0;e<st.size();e++)
    {
    if ((st.get(e)).equals(oldOne))
    st.set(e, newOne);
    }
    }

    public static void removeDup(ArrayList<String> st)
    {
    for (int d=0;d<st.size();d++)
    {
    for(int b=0;f<st.size();f++)
    {
    if((st.get(d)).equals(st.get(f)) && d!=b)
    {
    st.remove(d);
    }
    }
    }
    }

    }


    What should I add to fix it? PLEASE PLEASE PLEASE HELP!


  2. #2
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    Default Re: PLEASE HELP WITH JAVA ARRAYLISTS! Thanks.

    Welcome to the forum! Please read this topic to learn how to post code in code or highlight tags and other useful info for newcomers.

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