Chapter 19, Problem 1MC

A list is a collection that _____.

1. a. associates keys with elements
2. b. assigns an index to each of its elements
3. c. is implemented by the JList class
4. d. none of the above

Program Description Answer

A list is a collection that “assigns an index to each element in a list”.

Hence, the correct answer is option “B”.

Explanation of Solution

List:

• A list is a collection that stores its element in a location-based order.
• Each element in a list is related with an index that matches to its location within the list. That is the first element contains index 0, the second element contains index 1 and so on.
• Storage allocation for the elements of a list takes place in two methods such as contiguous allocation and linked allocation.
  • Continuous allocation:
    • Array-based lists use this allocation.
    • It assigns storage for consecutive list elements in consecutive memory locations.
  • Linked allocation:
    • This allocation does not require consecutive memory locations to store list elements.
    • It uses a pointer to store each element in a list.

Explanation for incorrect options:

A list is a collection that associates index with elements not keys.

Hence, the option “A” is wrong.

“JList” is a type of Java Swing package. It is a component that shows a set of objects and permits the user to choose more than one element from the list.

Hence, the option “C” is wrong.