1. Programming Fundamentals Chapter 4

2. Floating Point Numbers  Scientific notation 98 = 0.98 x 10 2 204.5 = 0.2045 x 10 3 -0.082167 = -0.82167 x10 -1  Sign bit; Fraction (Mantissa); Exponent SExponentFraction Sign Bit

3. Floating point arithmetic  Addition & Subtraction 0.45x10 2 + 0.32x10 1 = -0.45x10 2 - 32x10 1 =  Multiplication & Division 0.45x10 2 ÷ 0.32x10 -1 = 0.45x10 2 * 0.32x10 -1 =

4. Data Types  Type of quantities  Integer  Long Integer  Single  Double  String  Byte  Boolean  Currency  Date

5. Integer & Long Integer  Integer –Uses 2 bytes ( 2x8=16 bits ) of memory -32768  +32767 range -32768  +32767 range –No commas, like 20,400 –No decimals or fractions, like 2.45 or 4.00  Long Integer –Uses 4 bytes -2147483648  +2147483647 range -2147483648  +2147483647 range

6. Single & Double  Single –Use 4 bytes (32 bits) –Can have 7 significant digits -3.4E38  3.4E38 range -3.4E38  3.4E38 range  Double –Uses 8 bytes (64 bits) –Can have 15 significant digits -1.8D308  1.8D308 range -1.8D308  1.8D308 range

7. Byte & Currency  Byte –Unsigned numbers 0  255  Currency –8 Bytes -922,337,203,685,477.5808  -922,337,203,685,477.5808  +922,337,203,685,477.5808 –No truncation & rounding

8. String  Strings are non-numeric quantities, written within quotes –Examples  “Islam is the solution to world problems”  “CS101”  “-423.45”  “Rs. 32,400.55”  “TB stands for Tooni’s Blare & a notorious disease”

9. Constants & Variables  Each data type can be a constant or a variable  Constant –The contents of the memory remain fixed –Numeric or String pi  3.14 Speed Of Light  2.998e8 k  1.38e-23 Name Of My Hero  “Muhammad (pbuh)” e  “-1.6e-19”

10. Constants & Variables  Variables –The contents of a memory associated with a variable is allowed to change –A & B determine the contents of Sum and Product Read A Read B Sum = A + B Product = A*B

11. Declarations  Variables are declared at the beginning of a program using Dim –Reserve appropriate memory  Examples –Dim MidtermScore As Integer –Dim h As single, Frequency As Single –Dim Energy As Double –Dim StudentName As String –Dim CourseTitle As String*40

12. Memory Allocation Memory Allocation A_Integer A_Single

13. Variable Name Rules  A variable name must begin with an alphabet.  It should not be longer than 255 characters.  Special words, such as, Dim, If, Else, Case, etc. are not permitted.

14. Variable Name Rules  Some special characters are allowed within a variable name.  A period (full stop), %, # and & are not allowed. –Avoid special characters in a variable name.

15. Variable Name Rules  Visual Basic does not distinguish between upper and lower case letters. –AVARIABLE, AVariable, aVariable, avariable, etc. refer to the same memory location.

16. The Longest Variable Name  EvenThoughItIsHardToWriteOrReadAndMa nyOfUsMayNeverSeeOrWriteSuchLongVari ableNameYetVisualBasicAllowsTheUseOfT woHundredFiftyFiveCharactersForTheVaria bleName0123456789012345678901234567 89012345678901234567890123456789012 34567890123456789012345678901234567 89  255 characters

17. Suffix Notation Variable Data Type Index%Integer Counter& Long Integer TaxRate!Single Ratio#Double Name$String

18. Constants  Constants can be named like variables –Or remain un-named Const Name As String=“Muhammad (pbuh)” Const c As Single = 2.998E8 Const e As Double = -1.6D-19 22.56/7 –An effort to change the contents of a named constant will result in an error Assignment to constants not permitted

19. Operators  + (plus)AdditionShift + =  - (minus)Subtraction-  * (asterisk)MultiplicationShift + 8  / (slash)Division/  ^ (caret)ExponentiationShift + 6  \ (back slash) Integer division\  ModInteger remainder

20. Operations  2^3 = 8  10/8 = 1.25  10\8 = 1  8.6\2.7 = 3  10 Mod 8 = 2  2.3 Mod 2.1 = 0  2.3/1.2^2 = 2.3/1.44 = 1.5972

21. Hierarchy of Operations 1.(^) Exponentiation 2.(* or /)Multiplication & Division 3.(\)Integer Division 4.(Mod)Integer Remainder 5.(+ or -)Addition & Subtraction  Parentheses are used to change the order of operation.

22. Expressions  (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  -2^4 = -(2^4) = -16  (-2)^4 = 16

23. String Expressions Amount = “Ten” Denomination = “Thousand” Amount & “ “ & Denomination & “ Rupees”  Ten Thousand Rupees Amount + “ “ + Denomination + “ Rupees”  Ten Thousand Rupees

24. Assignment Salary = 12000 Tax = 4/100*Salary HouseRent = 1200 NetSalary = Salary - Tax - HouseRent

25. Library Functions  Abs  Y=Abs(-2)  Y = 2  Chr  Y=Chr(65)  Y = “A”  Exp  Y=Exp(2)  Y = e^2  Int  Y=Int(-2.9)  Y = -3

26. Library Functions  Rnd  Y=Rnd  Y gets a random number 0≤Y<1  Sgn  Y=Sgn(x)   Str  Y=Str(4.2)  Y = “4.2”  Val  Y=Val(“-3”)+Val(“2”)  Y = -3.1+2=-1.1  The string within the Val must appear like a number

27. Library Functions  Sin, Cos, Tan –Trigonometric functions  Arguments must be in RADIANS –Sin(x), Cos(u), Tan(w)  Date Y=Date  Current date mo/dy/Year  Sqr Y=Sqr(4)  Y = 2 =

28. Library Functions  Lcase Y=Lcase(“MyName”)  Y=“myname”  Ucase Y=Ucase(“MyName”)  Y = “MYNAME”  Len Y=Len(“MyName”)  Y=6

29. Library Functions  Left  Y=Left(“MyName”,3)  Y=“MyN”  Right  Y=Right(“MyName”,3)  Y=“ame”  Mid  Y=Mid(“MyName”,2,3)  Y=“yNa”  Log  Y=Log(72.4)  Y=log e (72.4)