Initializing
Java gives us a shortcut to both create and initialize an array.
char message[] = new char[3];
message[0] = 'H';
message[1] = 'i';
message[2] = '!';
We could do this same thing using the {} shortcut.
* The line below both creates the array of length 3 and initializes the array elements.
char message[] = {'H', 'i', '!'};
Using the Array Shortcut {}¶
We can only use the array shortcut by itself when we are declaring and initializing an array.
char message[] = {'H', 'i', '!'}; // Just fine.
char message[];
message = {'H', 'i', '!'}; // WILL NOT COMPILE
If we want to use the shortcut with a variable that already exists, we have to use new.
char message[] = {'H', 'i', '!'};
message = new char[] {'H', 'e', 'l', 'l', 'o'}; // reassign
Think of it as telling Java "reassign the variable message to point to this new char array containing the elements..."
Practice Exercise¶
When using the array shortcut, you can append a comma after the last element. The length of the array is still the number of values provided - there is no empty element for the space after that comma.
int[] ints = {0, 1, 2, }; // ints has only three elements
Drill¶
Arrays/src/drills/ArrayAccess2.java
* Access all the B grades in the grades array and output them to the screen.
* Use values from the firstNames and lastNames arrays to create the names Sarah Dobbs and Davey Jones. Output the names to the screen.
* Declare and initialize an array containing your pet's name and the street you grew up on. (If you do not have a pet, use the value null.)
* Reassign the same array and initialize it with your middle name and a U.S. President's last name. (Use the array shortcut. If you do not have a middle name, use the value null.)