COP 2800 (Java Programming I) Homework Assignment #6


Due: by the start of class on the date shown on the syllabus


Answer the following questions as briefly (but completely) as possible:

  1. How do you create a Date for the current time?  How do you display the current time?
  2. How do you do the following tasks?
    1. Create an ArrayList for storing double values?
    2. Append an object to a List?
    3. Insert an object at the beginning of a List?
    4. Find the number of objects in a List?
    5. Remove a given object from a List?
    6. Remove the last object from a List?
    7. Check whether a given object is in a List?
    8. Retrieve an object at a specified index from a List?
  3. Identify the errors in the following code fragment:
    ArrayList<String> list = new ArrayList<String>();
    list.add( "Denver" );
    list.add( "Austin" );
    list.add( new java.util.Date() );
    String city = list.get( 0 );
    list.set( 3, "Dallas" );
    System.out.println( list.get(3) );
  4. Suppose the ArrayList list contains duplicate elements.  Does the following code correctly remove all elements from list?  If not, correct the code.
    for ( int i = 0; i < list.size(); i++ )
       list.remove( element );
  5. Explain why the following code fragment displays [1, 3] rather than [2, 3].
    ArrayList<Integer> list = new ArrayList<Integer>();
    System.out.println( list );
  6. How do you create a Calendar object for the current time?
  7. For a Calendar object c, how do you get its year, month, date, hour, minute, and second?

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