Java Array Examples: Declaring and Initializing with Primitive Types

📚 Quick Study Guide

• 🔍 An array is a collection of elements of the same type stored in contiguous memory locations.
• 💡 In Java, arrays are objects.
• 📝 Primitive types in Java include `int`, `char`, `boolean`, `byte`, `short`, `long`, `float`, and `double`.
• 🔢 To declare an array, use the syntax: `dataType[] arrayName;` or `dataType arrayName[];`
• 🔨 To initialize an array, you can use: `arrayName = new dataType[arraySize];`
• 🧮 You can also declare and initialize in one line: `dataType[] arrayName = {value1, value2, ...};`
• ⏱️ Array indices start at 0 and go up to arraySize - 1.

Practice Quiz

1. Question 1: Which of the following is the correct way to declare an integer array named `numbers` in Java?
   1. int numbers;
   2. array numbers int;
   3. int[] numbers;
   4. numbers int[];
2. Question 2: How do you initialize an integer array named `values` with a size of 5?
   1. int[] values = {1, 2, 3, 4, 5};
   2. int[] values = new int[5];
   3. int values = new int[5];
   4. int[5] values = new int[];
3. Question 3: What is the index of the first element in an array?
   1. 1
   2. -1
   3. 0
   4. The size of the array
4. Question 4: Which of the following is the correct way to declare and initialize a character array with the values 'a', 'b', and 'c'?
   1. char[] letters = {'a', 'b', 'c'};
   2. char letters[] = ("a", "b", "c");
   3. char[] letters = new char[3]; letters = {'a', 'b', 'c'};
   4. char letters = {'a', 'b', 'c'};
5. Question 5: What is the default value of elements in an integer array after initialization with `new int[size]`?
   1. 1
   2. -1
   3. null
   4. 0
6. Question 6: How can you find the length (number of elements) of an array named `myArray`?
   1. myArray.length()
   2. length(myArray)
   3. myArray.size()
   4. myArray.length
7. Question 7: Which of the following is NOT a primitive data type in Java?
   1. int
   2. boolean
   3. String
   4. double