ECMM6018 Enterprise Networking For Electronic Commerce Tutorial 5

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ECMM6018 Enterprise Networking For Electronic
CommerceTutorial 5

• Server Side Scripting
• Perl

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What is it

• Server Side Language
• Cgi application resides in the /cgi-bin directory
  
• ! /opt/bin/perl
• Use CGI qw(standard)
• ASP, JSP

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Variable Types in Perl

• Scalar variable Scalar variables used to
  contain strings, integer Numbers and floating
  point numbers (decimals) 
• e.g. varname
• Indexed array A variable that can store
  different scalar values,e.g. numbers, decimals
• e.g. _at_arrayname
• accessed arraynamei
• Associative array elements of an associative
  array are referred to as "key" and "value" pairs
  
• e.g. array
• accessed arraykey pair
• Variable names should be restricted to just
  letters of the alphabet, i.e. leave out
  characters such as !, _at_, , , , , , , (, ),
  

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Mathematical Operators

• Addition
• - Subtraction
• Multiplication
• / Division
• Adds one to the value on the left, i.e. j,
  jj1
• -- Subtracts one from the value on the left j--,
  j j-1

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Assignment Operators

• Assigns what is on the right side to what is
  on the left e.g. a3
•  
• Adds the value of the right side to the left
  side and makes the variable on the left equal to
  it.
• e.g. a 3, aa3
•  
• - Subtracts the value of the right side to the
  left side and makes the variable on the left
  equal to it.
• e.g. a-3, aa-3

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Comparison Operators

• lt
• gt
• lt
• gt
• eq
• !
• Ne

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Conditional Statement

• If
• If Else
• If (condition)
• statement
• e.g. if (a!5)
• print Answer is not 5\n

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Conditional Statement

• If-Else
• If (condition)
• statement
• Else
• statement
• e.g. if (a!5)
• print Answer is not 5\n
• else
• print Answer is 5\n

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Conditional Statement

• if (stuff lt 5)
• print short!\n"
• elsif (stuff gt 6)
• print tall!\n"
• else
• print in between\n"

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Looping

• While
• For
• Foreach

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While Statement

• while (condition)
• code to be executed
• e.g. while (stuff lt6)
• print stuff\n
• stuff

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For Statement

• for (initialization test condition increment)
• code to be executed
• for (i 0 i lt stuff i)
• print "stuffi"

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For Each Statement

• foreach slotspace (_at_stuff)
• print "slotspace"
• foreach slotname (keys (stuff))
• print "stuffslotname"