Programming FundamentalsProgramming Fundamentals

Chapter 4Chapter 4

Floating Point NumbersFloating Point Numbers

Scientific notationScientific notation98 = 0.98 x 1098 = 0.98 x 1022

204.5 = 0.2045 x 10204.5 = 0.2045 x 1033

-0.082167 = -0.82167 x10-0.082167 = -0.82167 x10-1-1

Sign bit; Fraction (Mantissa); ExponentSign bit; Fraction (Mantissa); Exponent

S Exponent Fraction

Sign Bit

Floating point arithmeticFloating point arithmetic

Addition & SubtractionAddition & Subtraction0.45x100.45x1022 + 0.32x10 + 0.32x1011 = =

-0.45x10-0.45x1022 - 32x10 - 32x1011 = =

Multiplication & DivisionMultiplication & Division0.45x100.45x1022 ÷÷ 0.32x10 0.32x10-1-1 = =

0.45x100.45x1022 * 0.32x10 * 0.32x10-1-1 = =

Data TypesData Types Type of quantitiesType of quantities

IntegerInteger Long IntegerLong Integer SingleSingle DoubleDouble StringString ByteByte BooleanBoolean CurrencyCurrency DateDate

Integer & Long IntegerInteger & Long Integer

IntegerInteger– Uses 2 bytes ( 2x8=16 bits ) of memoryUses 2 bytes ( 2x8=16 bits ) of memory

-32768 -32768 +32767 range +32767 range– No commas, like 20,400No commas, like 20,400– No decimals or fractions, like 2.45 or 4.00No decimals or fractions, like 2.45 or 4.00

Long IntegerLong Integer– Uses 4 bytes Uses 4 bytes

-2147483648 -2147483648 +2147483647 range +2147483647 range

Single & DoubleSingle & Double

SingleSingle– Use 4 bytes (32 bits)Use 4 bytes (32 bits)– Can have 7 significant digitsCan have 7 significant digits

-3.4E38 -3.4E38 3.4E38 range 3.4E38 range

DoubleDouble– Uses 8 bytes (64 bits)Uses 8 bytes (64 bits)– Can have 15 significant digitsCan have 15 significant digits

-1.8D308 -1.8D308 1.8D308 range 1.8D308 range

Byte & CurrencyByte & Currency

ByteByte– Unsigned numbersUnsigned numbers

0 0 255 255

CurrencyCurrency– 8 Bytes8 Bytes

-922,337,203,685,477.5808 -922,337,203,685,477.5808 +922,337,203,685,477.5808 +922,337,203,685,477.5808

– No truncation & roundingNo truncation & rounding

StringString

Strings are non-numeric quantities, written Strings are non-numeric quantities, written within quoteswithin quotes– ExamplesExamples

““Islam is the solution to world problems”Islam is the solution to world problems” ““CS101”CS101” ““-423.45”-423.45” ““Rs. 32,400.55”Rs. 32,400.55” ““TB stands for Tooni’s Blare & a notorious disease”TB stands for Tooni’s Blare & a notorious disease”

Constants & VariablesConstants & Variables

Each data type can be a constant or a Each data type can be a constant or a variablevariable

ConstantConstant– The contents of the memory remain fixedThe contents of the memory remain fixed– Numeric or StringNumeric or String

pi pi 3.14 3.14

Speed Of Light Speed Of Light 2.998e8 2.998e8

k k 1.38e-23 1.38e-23

Name Of My Hero Name Of My Hero ““Muhammad (pbuh)Muhammad (pbuh)””

e e ““-1.6e-19-1.6e-19””

Constants & VariablesConstants & Variables

VariablesVariables– The contents of a memory associated with a The contents of a memory associated with a

variable is allowed to changevariable is allowed to change

– A & B determine the contents of Sum and A & B determine the contents of Sum and ProductProduct

Read ARead BSum = A + BProduct = A*B

DeclarationsDeclarations

Variables are declared at the beginning of a Variables are declared at the beginning of a program using program using DimDim

– Reserve appropriate memoryReserve appropriate memory

ExamplesExamples– Dim MidtermScore As IntegerDim MidtermScore As Integer– Dim h As single, Frequency As SingleDim h As single, Frequency As Single– Dim Energy As DoubleDim Energy As Double– Dim StudentName As StringDim StudentName As String– Dim CourseTitle As String*40Dim CourseTitle As String*40

Memory AllocationMemory Allocation

A_Integer

A_Single

Variable Name RulesVariable Name Rules

A variable name must begin with an A variable name must begin with an alphabet.alphabet.

It should not be longer than 255 It should not be longer than 255 characters.characters.

Special words, such as, Special words, such as, Dim, If, Else, Dim, If, Else, CaseCase, etc. are not permitted., etc. are not permitted.

Variable Name RulesVariable Name Rules

Some special characters are allowed Some special characters are allowed within a variable name.within a variable name.

A period (full stop), %, # and & are not A period (full stop), %, # and & are not allowed.allowed.

– Avoid special characters in a variable name.Avoid special characters in a variable name.

Variable Name RulesVariable Name Rules

Visual Basic does not distinguish between Visual Basic does not distinguish between upper and lower case letters.upper and lower case letters.

– AVARIABLE, AVARIABLE, AVariableAVariable, , aVariableaVariable, , avariableavariable, etc. refer to the same memory , etc. refer to the same memory location. location.

The Longest Variable NameThe Longest Variable Name

EvenThoughItIsHardToWriteOrReadAndMaEvenThoughItIsHardToWriteOrReadAndManyOfUsMayNeverSeeOrWriteSuchLongVarinyOfUsMayNeverSeeOrWriteSuchLongVariableNameYetVisualBasicAllowsTheUseOfTableNameYetVisualBasicAllowsTheUseOfTwoHundredFiftyFiveCharactersForTheVariawoHundredFiftyFiveCharactersForTheVariableName0123456789012345678901234567bleName0123456789012345678901234567890123456789012345678901234567890128901234567890123456789012345678901234567890123456789012345678901234567345678901234567890123456789012345678989

255 characters255 characters

Suffix NotationSuffix Notation

VariableVariable Data TypeData Type

Index%Index% IntegerInteger

Counter&Counter& Long IntegerLong Integer

TaxRate!TaxRate! SingleSingle

Ratio#Ratio# DoubleDouble

Name$Name$ StringString

ConstantsConstants

Constants can be named like variablesConstants can be named like variables– Or remain un-namedOr remain un-named

Const Name As String=Const Name As String=““Muhammad (pbuh)Muhammad (pbuh)””

Const c As Single = 2.998E8Const c As Single = 2.998E8

Const e As Double = -1.6D-19Const e As Double = -1.6D-19

22.522.5

6/76/7

– An effort to change the contents of a named An effort to change the contents of a named constant will result in an errorconstant will result in an errorAssignment to constants not permittedAssignment to constants not permitted

OperatorsOperators

+ (plus)+ (plus) AdditionAddition Shift + =Shift + = - (minus)- (minus) SubtractionSubtraction -- * (asterisk)* (asterisk) MultiplicationMultiplication Shift + 8Shift + 8 / (slash)/ (slash) DivisionDivision // ^ (caret)^ (caret) ExponentiationExponentiation Shift + 6Shift + 6 \ (back slash) \ (back slash) Integer divisionInteger division \\ ModMod Integer remainderInteger remainder

OperationsOperations

2^3 = 82^3 = 8 10/8 = 1.2510/8 = 1.25 10\8 = 110\8 = 1 8.6\2.7 = 38.6\2.7 = 3 10 Mod 8 = 210 Mod 8 = 2 2.3 Mod 2.1 = 02.3 Mod 2.1 = 0 2.3/1.2^2 = 2.3/1.44 = 1.59722.3/1.2^2 = 2.3/1.44 = 1.5972

Hierarchy of OperationsHierarchy of Operations

1.1. (^) (^) ExponentiationExponentiation

2.2. (* or /)(* or /) Multiplication & DivisionMultiplication & Division

3.3. (\)(\) Integer DivisionInteger Division

4.4. (Mod)(Mod) Integer RemainderInteger Remainder

5.5. (+ or -)(+ or -) Addition & SubtractionAddition & Subtraction

Parentheses are used to change the order Parentheses are used to change the order of operation.of operation.

ExpressionsExpressions

(2*(a+b)^2 + 3*c^2)^(3/2)(2*(a+b)^2 + 3*c^2)^(3/2)

(2*(a+b)^2 + 3*c^2)^3/2(2*(a+b)^2 + 3*c^2)^3/2

-x + y^2-x + y^2 -2^4 = -(2^4) = -16-2^4 = -(2^4) = -16 (-2)^4 = 16(-2)^4 = 16

2 2 3 2[2( ) 3 ]a b c

2 2 3[2( ) 3 ]

2

a b c

2x y

String ExpressionsString Expressions

Amount = “Ten”Amount = “Ten”

Denomination = “Thousand”Denomination = “Thousand”

Amount & “ “ & Denomination & “ Rupees”Amount & “ “ & Denomination & “ Rupees”

Ten Thousand RupeesTen Thousand Rupees

Amount + Amount + “ ““ “ + Denomination + “ Rupees” + Denomination + “ Rupees”

Ten Thousand RupeesTen Thousand Rupees

AssignmentAssignment

Salary = 12000Salary = 12000

Tax = 4/100*SalaryTax = 4/100*Salary

HouseRent = 1200HouseRent = 1200

NetSalary = Salary - Tax - HouseRentNetSalary = Salary - Tax - HouseRent

Library FunctionsLibrary Functions

AbsAbs Y=Abs(-2)Y=Abs(-2) Y = 2Y = 2

ChrChr Y=Chr(65)Y=Chr(65) Y = “A”Y = “A”

ExpExp Y=Exp(2)Y=Exp(2) Y = e^2Y = e^2

IntInt Y=Int(-2.9)Y=Int(-2.9) Y = -3Y = -3

Library FunctionsLibrary Functions

RndRnd Y=RndY=Rnd Y gets a random number 0Y gets a random number 0≤Y<1≤Y<1

SgnSgn Y=Sgn(x)Y=Sgn(x)

StrStr Y=Str(4.2)Y=Str(4.2) Y = “4.2”Y = “4.2”

ValVal Y=Val(“-3”)+Val(“2”)Y=Val(“-3”)+Val(“2”) Y = -3.1+2=-1.1Y = -3.1+2=-1.1

The string within the Val must appear like a numberThe string within the Val must appear like a number

1 0

0 0

1 0

Y x

Y x

Y x

Library FunctionsLibrary Functions

Sin, Cos, TanSin, Cos, Tan– Trigonometric functionsTrigonometric functions

Arguments must be in RADIANSArguments must be in RADIANS– Sin(x), Cos(u), Tan(w)Sin(x), Cos(u), Tan(w)

DateDateY=DateY=Date Current date mo/dy/Year Current date mo/dy/Year

SqrSqrY=Sqr(4)Y=Sqr(4) Y = 2 = Y = 2 = 4

Library FunctionsLibrary Functions

LcaseLcaseY=Lcase(“MyName”) Y=Lcase(“MyName”) Y=“myname” Y=“myname”

UcaseUcaseY=Ucase(“MyName”) Y=Ucase(“MyName”) Y = “MYNAME” Y = “MYNAME”

LenLenY=Len(“MyName”) Y=Len(“MyName”) Y=6 Y=6

Library FunctionsLibrary Functions

LeftLeft Y=Left(“MyName”,3) Y=Left(“MyName”,3) Y=“MyN” Y=“MyN”

RightRight Y=Right(“MyName”,3) Y=Right(“MyName”,3) Y=“ame” Y=“ame”

MidMid Y=Mid(“MyName”,2,3) Y=Mid(“MyName”,2,3) Y=“yNa” Y=“yNa”

LogLog Y=Log(72.4) Y=Log(72.4) Y=log Y=logee(72.4)(72.4)