COMPUTER PROGRAMMING I

Objective 7.03 Apply Built-in Math Class

Functions

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Objects/Classes and Methods in Visual Basic 

An object is a structure containing data and methods that manipulate the data.

Almost everything you do in Visual Basic is associated with objects. If you are new to object-oriented programming, the following terms and concepts will help you get started.

Classes and Objects

The words "class" and "object" are used so much in object-oriented programming that it is easy to get the terms mixed up. Generally speaking, a class is an abstract representation of something, whereas an object is a usable example of the thing the class represents.

Objects/Classes and Methods in Visual Basic 

Methods – Functions

Methods are operations that can be performed on data. A method may take some input values through its parameters and may return a value of a particular data type. There are two types of methods in VB: Sub Procedures and Functions.

For this Unit, we will discuss two built in classes with built in Functions:

The Math and String classes.

Math Class Functions

The Math class provides programmers with numerous built-in functions.

We will only look at a few of these functions.Abs(num)

Returns the absolute value of a positive or negative number

Sqrt(num) Returns the square root of a number

Sign(num) Returns the sign of a number

Round (num, places) Returns number nearest to the specified value.

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Using Abs(num)

The Abs() function returns the absolute value of the number and works with the following data types: Decimal, Double, Integer, SingleAbs() Function intNum Value

after execution

intNum = Math.Abs(4) 4

sngNum = Math.Abs(-4.123)

4.123

intNum = Math.Abs(0) 0

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Using Sqrt(num)

Sqrt(num) Returns the square root of a number as a double

Sqrt() Function dblNum Value after execution

dblNum = Math.Sqrt(4)

2.0

dblNum = Math.Sqrt(0)

0.0

dblNum = Math.Sqrt(-4)

NaN (not a number)(NaN represents a value that is not a number)

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Using Sign(num)

The Sign() function works with the following data types: Decimal, Double, Int16, Int32, Int64, SByte, Single

Sign() Function intNum Value after execution

intNum = Math.Sign(4)

1

intNum = Math.Sign(-4)

-1

intNum = Math.Sign(0)

0

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Round Function

The Round() function works with either a decimal or a double. The variable/value that represents the number of places should be an Integer.

Round() Function dblNum Value after execution

dblNum = Math.Round(5.23651, 2)

5.24

decNum = Math.Round(5.23651)

5.0

dblNum = Math.Round(5.5) 6.0

decNum = Math.Round(5.225, 2)

5.23

Note that 5 does round up here.

More info?

This PowerPoint provided an overview of several methods in the Math class in Visual Studio.

For more information on this topic http://msdn.microsoft.com/en-us/library/32s6akha(v=

VS.90).aspx http://msdn.microsoft.com/en-us/library/system.math.

aspx