Mathematical Functions In VB

VB is rich of variuos inbuilt functions. The mathematical functions are very useful and important in programming because very often we need to deal with mathematical concepts in programming such as chance and probability, variables, mathematical logics, calculations, coordinates, time intervals and etc. The common mathematical functions in Visual Basic are Rnd, Sqr, Int, Abs, Exp, Log, Sin, Cos, Tan , Atn, Fix and Round.

(i) Rnd is very useful when we deal with the concept of chance and probability. The Rnd function returns a random value between 0 and 1. In Example 1. When you run the program, you will get an output of 10 random numbers between 0 and 1. Randomize Timer is a vital statement here as it will randomize the process.

Example 1:

Private Sub Form_Activate

Randomize Timer

For x=1 to 10

Print Rnd

Next x

End Sub

Random numbers in its original form are not very useful in programming until we convert them to integers. For example, if we need to obtain a random output of 6 random integers ranging from 1 to 6, which make the program behave as a virtual die, we need to convert the random numbers using the format Int(Rnd*6)+1. Let’s study the following example:

In this example, Int(Rnd*6) will generate a random integer between 0 and 5 because the function Int truncates the decimal part of the random number and returns an integer. After adding 1, you will get a random number between 1 and 6 every time you click the command button. For example, let say the random number generated is 0.98, after multiplying it by 6, it becomes 5.88, and using the integer function Int(5.88) will convert the number to 5; and after adding 1 you will get 6.

In this example, you place a command button and change its caption to ‘roll die’. You also need to insert a label into the form and clear its caption at the designing phase and make its font bigger and bold. Then set the border value to 1 so that it displays a border; and after that set the alignment to center. The statement Label1.Caption=Num means the integer generated will be displayed as the caption of the label.

Example 2:

Dim num as integer

Private Sub Command1_Click ( )

Randomize Timer



End Sub
The Numeric Functions

The numeric functions are Int, Sqr, Abs, Exp, Fix, Round and Log.

a) Int is the function that converts a number into an integer by truncating its decimal part and the resulting integer is the largest integer that is smaller than the number. For example, Int(2.4)=2, Int(4.8)=4, Int(-4.6)= -5, Int(0.032)=0 and so on.

b) Sqr is the function that computes the square root of a number. For example, Sqr(4)=2, Sqr(9)=2 and etc.

c) Abs is the function that returns the absolute value of a number. So Abs(-8) = 8 and Abs(8)= 8.

d) Exp of a number x is the value of ex. For example, Exp(1)=e1 = 2.7182818284590

e) Fix and Int are the same if the number is a positive number as both truncate the decimal part of the number and return an integer. However, when the number is negative, it will return the smallest integer that is larger than the number. For example, Fix(-6.34)= -6 while Int(-6.34)=-7.

f) Round is the function that rounds up a number to a certain number of decimal places. The Format is Round (n, m) which means to round a number n to m decimal places. For example, Round (7.2567, 2) =7.26

g) Log is the function that returns the natural Logarithm of a number. For example,

Log 10= 2.302585
Example 3

This example computes the values of Int(x), Fix(x) and Round(x,n) in a table form. It uses the Do Loop statement and the Rnd function to generate 10 numbers. The statement x = Round (Rnd * 7, 7) rounds a random number between 0 and 7 to 7 decimal places. Using commas in between items will create spaces between them and hence a table of values can be created. The program and output are shown below

Private Sub Form_Activate ()

n = 1

Print " n", " x", "Int(x)", "Fix(x)", "Round(x, 4)"

Do While n < 11

Randomize Timer

x = Round (Rnd * 7, 7)

Print n, x, Int(x), Fix(x), Round(x, 4)

n = n + 1


End Sub

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Visual Basic-6 has emerged as one of the standard Windows Programming Language and it has become a must for all Software people for developing Applications in Visual Environment. So it is, one must learn Visual Basic-6.

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Visual Basic-6 has its origin in Basic which was developed round about the year 1960, when high level languages were just being introduced to the computer community. Microsoft has made it extremely powerful by gearing all its good features to the Windows environment. Starting with the version 3 and then with 4, and then with 6, Visual Basic is now at version 6. Basic is a Procedure Oriented Language intended to implement single tasks in text based environment whereas Visual Basic is an Event Driven Language intended to implement Projects or Applications containing multiple tasks in Windows Environment.

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Structure of VB-6 Projects:

We said earlier that VB-6 implements projects or applications. A project is developed using one or more Forms. A Form is simply a window containing one or more Controls. Controls in VB consist of labels, text boxes, list boxes, combo boxes, scroll bars etc. which are the constituents of windows environment. It is only the controls that give VB, its immense power and so there is a lot of interest in creating more and more powerful controls. ActiveX controls mark a significant development in controls technology. In fact all controls in VB-6 are ActiveX controls, which have the extension .ocx. These controls have properties whose values can be initialized at design time and also varied during run time. The properties are something like variables. The controls are activated by codes written in a high level language. By associating our problem variables with the properties of the controls, our problem variables can be manipulated to give the problem solution. In summary we can say that a VB project is made of forms, controls and their properties and codes.

Integrated Development Environment:

The working environment in VB is often referred to as the Integrated Development Environment or IDE, because it integrates many different functions such as design, editing, compiling and debugging within a common environment. Since all our projects are developed only in the IDE, let us now have a brief look at its features. You will be able to understand their uses at the time of building projects. The VB IDE looks as shown in the figure.