In this tutorial, we will learn Arrays in Flowgorithm flowchart. The main advantage of the arrays is flexibility and ease of storing elements of same type.
What is an Array?
An Array is a data structure that holds elements of the same datatype in contiguous memory locations. We can store and access the array elements using the index or subscript.
For example, to store 5 elements we can declare one array variable of size 5. Without using arrays, we need to declare 5 different variables to store the elements. It is quite difficult for the programmer to remember and use variables as the number of elements increases.
In this example, we use fruits array variable. fruits is an array variable that stores different fruit names. The size of the array variable is 5.
Note that the array stores the names of the fruit names and not the fruit objects. The data type of the array elements is String.
Single Dimensional Array
Single dimensional arrays have only one dimension either a row or a column. The fruits array is an example of a single-dimensional array. We can refer to the single-dimensional array as a 1D array in short form. We need only one index to refer to the array element.
For example: fruits[i]
Two-dimensional arrays have both rows and columns. A chessboard is an example of a two-dimensional array. We can refer to the two-dimensional array as a 2D Array in short form. We need two index variables to refer to each array element. One index for the row and another for the column.
Each square can be thought of as an array element and can be referred to as
i is the index for the row and j is the index for the column.
In Flowgorithm, the i and j variables are called subscript variables. However, In Chess game terminology, the row is called rank and the column is called a file in a chessboard.
Normal Chess board with 8 rows and 8 columns.
Array index or subscript
We need to store and retrieve individual array elements using the array index. In the Flowgorithm flowchart, the index starts with 0. So, to access the 3rd element we can use 2 as the index.
The fifth fruit grapes is stored in array index 4.
fruits = “Grapes”
For an Array of size 5 the valid ranges of the subscript is from 0 to 4. In general for an array of size n, the valid range of subscript range is from o to n-1. Under any circumstances if we try to allot values to array subscript that is outside the valid range, we would get an error Bad Subscript. In Java programming language, we call this exception as ArrayIndexOutOfBoundsException.
Declare Array variable
We can declare array variables with Declare statement. Give a variable a name and check the checkbox Array? to make it as an array variable.
Specify the array elements data type in the Type: drop-down.
Specify the array size in the Array Size: textbox.
The declare symbol would look like:
String Array fruits
Let’s create a sample flowchart to declare the array variable and store the elements in the array.
We have hard-coded the array values using the assign statements. Every time the flowchart runs the array elements do not change and are fixed. In next article we will see how to populate the array using loop statement and take input from user.
Array elements with User Input
Flowgorithm Tutorials Link: