Microsoft Visual Basic 2005: Reloaded Second Edition Chapter 8 Arrays
Objectives After studying this chapter, you should be able to: Declare and initialize a one-dimensional array Store data in a one-dimensional array Display the contents of a one-dimensional array Code a loop using the For Each…Next statement Access an element in a one-dimensional array Microsoft Visual Basic 2005: Reloaded, Second Edition
Objectives (continued) Search a one-dimensional array Compute the average of a one-dimensional array’s contents Find the highest entry in a one-dimensional array Update the contents of a one-dimensional array Sort a one-dimensional array Microsoft Visual Basic 2005: Reloaded, Second Edition
Objectives (continued) Create and manipulate parallel one-dimensional arrays Create and initialize a two-dimensional array Store data in a two-dimensional array Search a two-dimensional array Microsoft Visual Basic 2005: Reloaded, Second Edition
Using Arrays Simple variable (or scalar variable): a variable that is unrelated to any other variable in memory Array: A group of variables with the same name and data type that are related in some way Used to temporarily store related data in memory Increases the efficiency of a program Commonly used arrays: One-dimensional Two-dimensional Microsoft Visual Basic 2005: Reloaded, Second Edition
One-Dimensional Arrays Can be viewed as a column of variables Subscript: A unique number that identifies each variable in a one-dimensional array Starts at 0 for first element in the array Use array name and subscript to refer to each individual variable in the array Microsoft Visual Basic 2005: Reloaded, Second Edition
One-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
One-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
One-Dimensional Arrays (continued) Element: an individual variable in the array When an array is declared: Each element in the array is initialized if no values are provided Initial values can be specified for elements Microsoft Visual Basic 2005: Reloaded, Second Edition
Storing Data in a One-Dimensional Array Microsoft Visual Basic 2005: Reloaded, Second Edition
Manipulating One-Dimensional Arrays Array elements can be used like any other variable Examples: Display the contents of an array Access an array element using its subscript Search the array Calculate the average of data stored in a numeric array Find the highest value stored in an array Update array elements Sort array elements Microsoft Visual Basic 2005: Reloaded, Second Edition
Displaying the Contents of a One-Dimensional Array Microsoft Visual Basic 2005: Reloaded, Second Edition
Displaying the Contents of a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Displaying the Contents of a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
The For Each…Next Statement Used to code a loop which processes each element in a group or array Creates a variable used to represent each item in the group or array Data type of the element must match the data type of the group Microsoft Visual Basic 2005: Reloaded, Second Edition
The For Each…Next Statement (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Using the Subscript to Access an Element in a One-Dimensional Array Microsoft Visual Basic 2005: Reloaded, Second Edition
Using the Subscript to Access an Element … (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Using the Subscript to Access an Element … (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Searching a One-Dimensional Array Microsoft Visual Basic 2005: Reloaded, Second Edition
Searching a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Searching a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Searching a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Calculating the Average Amount Stored in a One-Dimensional Numeric Array Sample application: Find the average from an array of test scores Length property: number of elements in the array Microsoft Visual Basic 2005: Reloaded, Second Edition
Calculating the Average Amount Stored in a One-Dimensional Numeric Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Calculating the Average Amount Stored in a One-Dimensional Numeric Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Calculating the Average Amount Stored in a One-Dimensional Numeric Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Calculating the Average Amount Stored in a One-Dimensional Numeric Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Determining the Highest Value Stored in a One-Dimensional Array Microsoft Visual Basic 2005: Reloaded, Second Edition
Determining the Highest Value Stored in a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Determining the Highest Value Stored in a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Updating the Values Stored in a One-Dimensional Array Microsoft Visual Basic 2005: Reloaded, Second Edition
Updating the Values Stored in a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Updating the Values Stored in a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Updating the Values Stored in a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Sorting the Data Stored in a One-Dimensional Array Sorting: arranging data in a specific order Ascending: first element is smallest, last element is largest Descending: first element is largest, last element is smallest Array.Sort method: used to sort elements in a one-dimensional array in ascending order Array.Reverse method: used after Array.Sort method to change to descending order Microsoft Visual Basic 2005: Reloaded, Second Edition
Sorting the Data Stored in a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Sorting the Data Stored in a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Sorting the Data Stored in a One-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Parallel One-Dimensional Arrays Microsoft Visual Basic 2005: Reloaded, Second Edition
Parallel One-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Parallel One-Dimensional Arrays (continued) Parallel arrays: Two or more arrays whose elements are related by their position in the arrays Microsoft Visual Basic 2005: Reloaded, Second Edition
Parallel One-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Parallel One-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Parallel One-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Parallel One-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Two-Dimensional Arrays Resembles a table with rows and columns Each element is identified by a unique combination of two subscripts: (row, column) Subscripts are zero-relative Microsoft Visual Basic 2005: Reloaded, Second Edition
Two-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Two-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Two-Dimensional Arrays (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Two-Dimensional Arrays (continued) Declared with highest row subscript and highest column subscript (zero-relative) Number of rows = highest row subscript + 1 Number of columns = highest column subscript + 1 Can specify initial values for array elements If no initial values are declared, array elements are automatically initialized Microsoft Visual Basic 2005: Reloaded, Second Edition
Storing Data in a Two-Dimensional Array Microsoft Visual Basic 2005: Reloaded, Second Edition
Storing Data in a Two-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Searching a Two-Dimensional Array Microsoft Visual Basic 2005: Reloaded, Second Edition
Searching a Two-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Searching a Two-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Searching a Two-Dimensional Array (continued) Microsoft Visual Basic 2005: Reloaded, Second Edition
Programming Tutorial Microsoft Visual Basic 2005: Reloaded, Second Edition
Programming Example Microsoft Visual Basic 2005: Reloaded, Second Edition
Summary Arrays: a group of related variables with the same name and same data type Array element: one item in the array One-dimensional array: each element is uniquely identified by its position (subscript) in the array Two-dimensional array: each element is uniquely identified by its position (row and column subscripts) in the array Subscripts are zero-relative Microsoft Visual Basic 2005: Reloaded, Second Edition
Summary (continued) Number of elements in an array is the highest subscript value + 1 For Each...Next statement: used to loop through all the elements in an array Length property: returns the number of elements in an array Array.Sort method: sorts the elements in a one-dimensional array in ascending order Array.Reverse method: reverses the order of elements in a one-dimensional array Microsoft Visual Basic 2005: Reloaded, Second Edition