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VB.Net program to search an item in array using interpolation search

Here, we are going to learn how to search an item in array using interpolation search in VB.Net?
Submitted by Nidhi, on December 08, 2020 [Last updated : March 06, 2023]

Search an item in array using interpolation search

Here, we will create an array of integers and then read elements from the user, and search item in the array using binary search. The interpolation search is used to search item into the sorted array, it is similar to binary search but calculation to find middle element is different. We can say that it is the improved version of binary search.

Program/Source Code:

The source code to search an item in array using interpolation search is given below. The given program is compiled and executed successfully.

VB.Net code to search an item in array using interpolation search

'VB.Net program to search an item in array using 
'interpolation search.

Module Module1
    Sub Main()
        Dim arr As Integer() = New Integer(5) {}
        Dim item As Integer = 0
        Dim flag As Integer = 0

        Dim first As Integer = 0
        Dim last As Integer = 0
        Dim middle As Integer = 0
        Dim i As Integer = 0

        Console.WriteLine("Enter array elements: ")
        For i = 0 To 4 Step 1
            Console.Write("Element[{0}]: ", i)
            arr(i) = Integer.Parse(Console.ReadLine())
        Next

        Console.WriteLine("Enter item for searching: ")
        item = Integer.Parse(Console.ReadLine())

        first = 0
        last = 4
        middle = (first + last) / 2

        While first <= last
            middle = first + (((last - first) / (arr(last) - arr(first))) * (item - arr(first)))

            If (arr(middle) = item) Then
                flag = middle
                GoTo out
            Else
                If (arr(middle) < item) Then
                    first = middle + 1
                Else
                    last = middle - 1
                End If
            End If
        End While
out:
        If flag <> 0 Then
            Console.WriteLine("Item found at index {0} in array", flag)
        Else
            Console.WriteLine("Item is not found")
        End If
    End Sub
    
End Module

Output

Enter array elements:
Element[0]: 11
Element[1]: 22
Element[2]: 33
Element[3]: 44
Element[4]: 55
Enter item for searching:
22
Item found at index 1 in array
Press any key to continue . . .

Explanation

In the above program, we created a module Module1 that contains a function Main(). In the Main() we created an array arr of five elements and five variables item, flag, first , last, and middle that are initialized with 0.

Console.WriteLine("Enter array elements: ")
For i = 0 To 4 Step 1
    Console.Write("Element[{0}]: ", i)
    arr(i) = Integer.Parse(Console.ReadLine())
Next

In the above code, we read the elements of the array from the user.

Console.WriteLine("Enter item for searching: ")
item = Integer.Parse(Console.ReadLine())

first = 0
last = 4
middle = (first + last) / 2

While first <= last
    middle = first + (((last - first) / (arr(last) - arr(first))) * (item - arr(first)))

    If (arr(middle) = item) Then
        flag = middle
        GoTo out
    Else
        If (arr(middle) < item) Then
            first = middle + 1
        Else
            last = middle - 1
        End If
    End If
End While
out:
If flag <> 0 Then
    Console.WriteLine("Item found at index {0} in array", flag)
Else
    Console.WriteLine("Item is not found")
End If

In the above code, we used interpolation search technique; it is the improved version of binary search. Here, we used different formula to calculate middle element.

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