Building Applications

Transcription

1 V B. N E T P r o g r a m m i n g, T h e B a s i c C o n c e p t s a n d To o l s E n g. H a s a n A l h o u r i Building Applications analyzing designing coding testing deploying Eng. Hasan Alhouri 1

2 Programming Steps Writing the code in a high level language Compiling to an assembly Executing the executable program The structure solution Project1 project2 module1 module2 Class1 Class2 sub1 sub2 function1 function2 Eng. Hasan Alhouri 2

3 Notes about the structure The program has to be included within a solution. The program has to has one module at least. There is a module at which the compiler begins; it s called the main module. The main module has to has one subroutine at least, which has the name main. Each module has to be saved as.vb file. The Simplest Program module module1 sub main() console.writeline( the smallest program ) end sub end module Module definition Main() is a mandatory sub in the console application A command that print something on the screen The compiler need to know that the sub ends at some place The compiler need to know that the module ends at some place Eng. Hasan Alhouri 3

4 The Keywords module, sub, end module and end sub are keywords. The keywords are known by the compiler. They tell it some things. They have to be written correctly. They can t be used for other purposes. Printing Texts writeline( the smallest program ) write( the smallest ) write( program ) writeline() Eng. Hasan Alhouri 4

5 Name Spaces module module1 omit this sub main() console.writeline( the smallest program ) end sub end module Imports system.console module module1 sub main() writeline( the smallest program ) end sub end module and add this A module with more than a subroutine Imports system.console module module1 sub main() writeline( first time ) print_hello() writeline( first time ) print_hello() writeline( that s enough ) end sub sub print_hello() writeline( Hello ) end sub end module Eng. Hasan Alhouri 5

6 The scenario sub main() writeline( first time ) print_hello() writeline( first time ) print_hello() writeline( enough ) end sub sub print_hello() writeline( Hello ) end sub Main() writeline( first time ) print_hello() print_hello() writeline( enough ) Print_hello() writeline( Hello ) writeline( Hello ) Comments module module1 sub main() console.writeline( the smallest program ) console.writeline( comments ) this is a comment this line will not be executed end sub end module Eng. Hasan Alhouri 6

7 Breaking out a long command writeline( this is a tall command &_ so we have to break it out into two &_ lines ) writeline( this is a tall command so we have to break it out into two lines ) More than a command on a line writeline( this is so funny ):writeline( that we are learning programming ) writeline( this is so funny ) writeline( that we are learning programming ) Eng. Hasan Alhouri 7

8 Variables dim x1 as integer x1 0 x1=12 x1 12 dim x2 as integer=3 x2 3 dim x3 as integer=4.3 x3 4 dim x4 as integer=4.7 x4 5 Variables Special case: When the decimal part is 5 Even integer part rounded down dim x5 as integer=4.5 x5 4 dim x6 as integer=3.5 x6 4 Odd integer part rounded up Eng. Hasan Alhouri 8

9 Variables dim x7,x8 as integer x7 x8 0 0 dim x9 as integer, x10 as double x9 x dim x11 as integer=21, x12 as double=2.7 x11 x Variables dim c1 as char c1 c2= A c2 A dim c3 as char= 312 c3 3 Eng. Hasan Alhouri 9

10 Variables dim s1 as string s1 s1= Hello s1 Hello dim s2 as string= Samer s2 Samer writeline(s1 & & s2) Hello Samer Variables Long (Int64) Integer (Int32) Short (Int16) Byte Eng. Hasan Alhouri 10

11 Variables Double Single E E E E+308 Getting Information about Variables dim x1,x2,x3 as integer x1=31 : x2=0 : x3= -17 x1 x2 x writeline(sign(x1)) writeline(sign(x2)) writeline(sign(x3)) Eng. Hasan Alhouri 11

12 Getting Information about Variables dim x1as integer writeline(x1.min()) writeline(x1.max()) The Arithmetical Operations writeline(3+4) 7 writeline(3-4) -1 writeline(3*4) 12 writeline(3^4) 81 Eng. Hasan Alhouri 12

13 The Arithmetical Operations writeline(13/4) 4.25 writeline(13\4) 4 writeline(13 mod 4) 1 Priority Order 12/4-2*4^3*(40 - (20/5+32)) 12/4-2*4^3*(40 - (4+32)) 12/4-2*4^3*(40-36) 12/4-2*4^3*4 12/4-2*64*4 3-2*64* * Eng. Hasan Alhouri 13

14 Some Useful Built-in Math Functions sign(x) sign(319) sign(0) sign(-25) x > 0 x = 0 x < Some Useful Built-in Math Functions abs(x) +x abs(319) 319 abs(-25) 25 Eng. Hasan Alhouri 14

15 The Boolean Data Type dim b1 as boolean dim b2 as boolean= dim b3 as boolean= dim b4 as boolean= Hello boys dim b5 as boolean=44 b1 b2 b3 b4 b5 Comparing writeline(3+4) writeline(3=4) writeline(3>4) writeline(3<4) Eng. Hasan Alhouri 15

16 Comparing writeline(3>=4) writeline(3<=4) writeline(3<>4) writeline(3+5=12-1*10) Logical Operation C1 C2 C1 AND C2 C1 OR C2 NOT(C1) Eng. Hasan Alhouri 16

17 Comparing writeline(3>=4 and 6=5) writeline(3>=4 or 5-1=4) writeline(not(3>=4)) writeline(3=2 and (4=16 or 1>9)) Conditions Syntax If(condition1) then Statements1 Elseif(condition2) then Statements2 Elseif(condition3) then Statements3 Else Statements4 End if Example If(a=b) then writeline(a & is equal to & b) Elseif(a>b) then writeline(a & is larger than & b) Elseif(a<b) then writeline(a & is smaller than & b) Else writeline( can t decide ) End if Eng. Hasan Alhouri 17

18 Notes About The Conditions If is necessary always and it must be closed by End if but Elseif and Else are optional. Syntax If(condition1) then Statements1 End if Example If(a>b) then writeline(a & is larger than & b) End if Notes About The Conditions When the statements are one line it may be placed directly after the then at the same line with If and End if could be omitted. Syntax If(condition) then Statements Example If(a>b) then writeline(a & > & b) Eng. Hasan Alhouri 18

19 Notes About The Conditions The condition may be any logical expression that could be evaluated to or. Syntax If(condition1) then Statements1 End if Example If(a>b and s= Hello or b=7) then writeline( it s ok ) End if Notes About The Conditions It s possible to include a If statement inside another If statement. Syntax If(condition1) then Statements1 If(condition2)then Statements2 End if Statement3 End if Example If(a<>0 and b<>0) then If(a<b)then writeline(b & is the length ) End if End if Eng. Hasan Alhouri 19

20 The GOTO Statement It s used for two reasons: -To return to a previous line of the code. - Or to skip some lines of the code. Example1 p1: If(a<10) then a=a+1 GOTO p1 End if Example2 If(a<>0) then GOTO p2 End if writeline( this will be skipped ) p2: Making Loops With GOTO -To returning to a previous line with GOTO may produce a loop. Example1 dim a as integer=2 p1: If(a<7) then a=a+1 writeline(a) GOTO p1 End if Eng. Hasan Alhouri 20

21 The While Loop Syntax While (condition) Statements End while Example1 dim a as integer=2 while(a<7) a=a+1 writeline(a) End while The For Loop Syntax For variable=initial to final step step Statements Next Example1 Dim i as integer For i=3 to 11 step 2 writeline(i) Next Eng. Hasan Alhouri 21

22 Notes About The For Loop If the step were omitted; its value will be +1 Example Dim i as integer For i=3 to 7 writeline(i) Next Notes About The For Loop The step could be negative; and then the final value must be smaller than the initial value. Example Dim i as integer For i=13 to 7 step -2 writeline(i) Next Eng. Hasan Alhouri 22

23 Notes About The For Loop The loop variable could be defined inside the loop; and then it will be local at the loop only. Example For i as integer =13 to 7 step -2 writeline(i) Next Breaking the Loop - exit For i as integer =1 to 10 writeline(i) if (i=5) then exit for end if writeline (i^2) Next Breaking the loop at a condition, and jumping to the next command after the loop Eng. Hasan Alhouri 23

24 Breaking the Loop - continue For i as integer =1 to 10 writeline(i) if (i=5) then continue for end if writeline (i^2) Next Breaking the loop at a condition, and jumping to the next iteration in the loop Arrays Vector of 3 elements 2D array of 2 rows and 3 columns A B A(0) A(1) A(2) B(1,2) dim a() as integer a=new integer(2) {2,4,9} dim b(,) as integer a=new integer(1,2) {{3,5,-7},{11,2,50}} Eng. Hasan Alhouri 24

25 Many Ways to Define Arrays Dim a(3), b() As Integer b = New Integer(3) {} b is still nothing in the memory now b is a vector of 3 0's b = New Integer() {1, 12, 11, 10} [0 0 0] a way to fill the elements a [ ] b (0)=33 to access an element and change it a b a b b a b [0 0 0] [0 0 0] [0 0 0] [0 0 0] [ ] Information about Arrays A 2 4 dim a() as integer a=new integer(2) {2,4,9} 9 3 B dim b(,) as integer b=new integer(1,2) {{3,5,-7},{11,2,50}} writeline(a.length) writeline(a.rank) 3 1 writeline(b.length) writeline(b.rank) writeline(b.getlength(0)) writeline(a.length) 3 writeline(b.getlength(1)) 3 Eng. Hasan Alhouri 25

26 Sorting Arrays 1D A dim a() as integer a=new integer(5) {5, 1, 2, 9, 6, 3} Array.Sort(a) Array.Sort(a) Array.Reverse(a) dim b(,) as integer b=new integer(1,2) {{3,5,-7},{11,2,50}} Dim a(b.length - 1) As Integer Dim k As Integer Sorting Arrays 2D a will be used temporary to store the elements of b as a vector For i As Integer = 0 To b.getlength(0) - 1 For j As Integer = 0 To b.getlength(1) - 1 a(k) = b(i, j) k = k + 1 Next Next Filling a with the elements of b Array.Sort(a) k=0 3 B 11 Sorting a Resetting k to For i As Integer = 0 To b.getlength(0) - 1 For j As Integer = 0 To b.getlength(1) - 1 b(i, j)=a(k) k = k + 1 Next Next Filling b with the sorted elements Eng. Hasan Alhouri 26

27 Printing Arrays A dim a() as integer a=new integer(3) {5, 2, 7, 3} For i As Integer = 0 To a.length- 1 Write(vbTab & a(i)) Next Printing Arrays B Dim b(,) As Integer b = New Integer(1, 2) {{3, 5, -7}, {11, 2, 50}} For i As Integer = 0 To b.getlength(0) - 1 For j As Integer = 0 To b.getlength(1) - 1 Write(vbTab & b(i, j)) Next WriteLine() Next Eng. Hasan Alhouri 27

28 Referencing Arrays Dim b(,) As Integer b = New Integer(1, 2) {{3, 5, -7}, {11, 2, 50}} Creating the array b b Dim c(,) As Integer c = b c(0, 0) = 10 b(0,1)=25 c is another reference to the same array Changing an element in c or in b affects the same array b c b c Cloning Arrays Dim b(,) As Integer b = New Integer(1, 2) {{3, 5, -7}, {11, 2, 50}} Creating the array b Dim c(,) As Integer c = b.clone c is a new copy of b, so it s a different array b b c c(0, 0) = 10 b(0,1)=25 Changing an element in c affects only c, and changing an element in b affects only b b c Eng. Hasan Alhouri 28