![Arrays
An array is an indexed set of variables, such as
dancer[1], dancer[2], dancer[3],… It is like a set of
boxes that hold things.
A list is a set of items.
An array is a set of
variables that each
store an item.](https://image.slidesharecdn.com/array1-150626051946-lva1-app6892/85/Array1-2-320.jpg)
![Introducing Arrays
Array is a data structure that represents a collection
of the same types of data.
myList[0]
myList[1]
myList[2]
myList[3]
myList[4]
myList[5]
myList[6]
myList[7]
myList[8]
myList[9]
double[] myList = new double[10];
myList reference
An Array of 10
Elements
of type double](https://image.slidesharecdn.com/array1-150626051946-lva1-app6892/85/Array1-8-320.jpg)
![Declaring Array Variables
• datatype[] arrayname;
Example:
double[] myList;
• datatype arrayname[];
Example:
double myList[];](https://image.slidesharecdn.com/array1-150626051946-lva1-app6892/85/Array1-9-320.jpg)
![Creating Arrays
arrayName = new datatype[arraySize];
Example:
myList = new double[10];
myList[0] references the first element in the
array.
myList[9] references the last element in the
array.](https://image.slidesharecdn.com/array1-150626051946-lva1-app6892/85/Array1-10-320.jpg)
![Declaring and Creating
in One Step
• datatype[] arrayname = new
datatype[arraySize];
double[] myList = new double[10];
• datatype arrayname[] = new
datatype[arraySize];
double myList[] = new double[10];](https://image.slidesharecdn.com/array1-150626051946-lva1-app6892/85/Array1-11-320.jpg)
![Initializing Arrays
• Using a loop:
for (int i = 0; i < myList.length; i++)
myList[i] = i;
• Declaring, creating, initializing in one step:
double[] myList = {1.9, 2.9, 3.4, 3.5};
This shorthand syntax must be in one
statement.](https://image.slidesharecdn.com/array1-150626051946-lva1-app6892/85/Array1-13-320.jpg)
![Declaring, creating, initializing
Using the Shorthand Notation
double[] myList = {1.9, 2.9, 3.4, 3.5};
This shorthand notation is equivalent to the
following statements:
double[] myList = new double[4];
myList[0] = 1.9;
myList[1] = 2.9;
myList[2] = 3.4;
myList[3] = 3.5;](https://image.slidesharecdn.com/array1-150626051946-lva1-app6892/85/Array1-14-320.jpg)
Array1
- 1. Introduction to Data Structures
- 2. Arrays An array is an indexed set of variables, such as dancer[1], dancer[2], dancer[3],… It is like a set of boxes that hold things. A list is a set of items. An array is a set of variables that each store an item.
- 3. Arrays and Lists You can see the difference between arrays and lists when you delete items.
- 4. Arrays and Lists In a list, the missing spot is filled in when something is deleted.
- 5. Arrays and Lists In an array, an empty variable is left behind when something is deleted.
- 6. Arrays Arrays can be created in a similar manner, but more often they are created using the array visualization object from the Alice local gallery. The Array Visualization object has special properties and methods for manipulating the elements in an array.
- 7. Arrays Alice has a set of built-in functions that can be performed on arrays.
- 8. Introducing Arrays Array is a data structure that represents a collection of the same types of data. myList[0] myList[1] myList[2] myList[3] myList[4] myList[5] myList[6] myList[7] myList[8] myList[9] double[] myList = new double[10]; myList reference An Array of 10 Elements of type double
- 9. Declaring Array Variables • datatype[] arrayname; Example: double[] myList; • datatype arrayname[]; Example: double myList[];
- 10. Creating Arrays arrayName = new datatype[arraySize]; Example: myList = new double[10]; myList[0] references the first element in the array. myList[9] references the last element in the array.
- 11. Declaring and Creating in One Step • datatype[] arrayname = new datatype[arraySize]; double[] myList = new double[10]; • datatype arrayname[] = new datatype[arraySize]; double myList[] = new double[10];
- 12. The Length of Arrays • Once an array is created, its size is fixed. It cannot be changed. You can find its size using arrayVariable.length For example, myList.length returns 10
- 13. Initializing Arrays • Using a loop: for (int i = 0; i < myList.length; i++) myList[i] = i; • Declaring, creating, initializing in one step: double[] myList = {1.9, 2.9, 3.4, 3.5}; This shorthand syntax must be in one statement.
- 14. Declaring, creating, initializing Using the Shorthand Notation double[] myList = {1.9, 2.9, 3.4, 3.5}; This shorthand notation is equivalent to the following statements: double[] myList = new double[4]; myList[0] = 1.9; myList[1] = 2.9; myList[2] = 3.4; myList[3] = 3.5;
Editor's Notes
- #3: The Redo button will reverse the last use of the Undo button, restoring the previous action. The Ctrl-Y keyboard shortcut also can be used in place of the Redo button.
- #4: The Redo button will reverse the last use of the Undo button, restoring the previous action. The Ctrl-Y keyboard shortcut also can be used in place of the Redo button.
- #5: The Redo button will reverse the last use of the Undo button, restoring the previous action. The Ctrl-Y keyboard shortcut also can be used in place of the Redo button.
- #6: The Redo button will reverse the last use of the Undo button, restoring the previous action. The Ctrl-Y keyboard shortcut also can be used in place of the Redo button.
- #7: The Redo button will reverse the last use of the Undo button, restoring the previous action. The Ctrl-Y keyboard shortcut also can be used in place of the Redo button.
- #8: The Redo button will reverse the last use of the Undo button, restoring the previous action. The Ctrl-Y keyboard shortcut also can be used in place of the Redo button.