We shall review your impudence at a later date

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We shall review your impudence at a later date
http//www.imdb.com/title/tt0048960/

• David Niven in Around the World in 80 Days
  (1956)

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Computer Science 101Lecture 19
linuxvm.org/ Images/TuxonVM.gif

• Spring Semester 2008
• Friday, February 29
• Week 7/18
• Albert H. Carlson

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Announcements

• Due March 7 Midterm Essay
• Bring your FLASH drive to lab
• Bring your Castro Book on HTML to lab. Also,
  study the assigned reading to this point so you
  are familiar with it.

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5th Generation/Research

• The newest experimental languages
• Often OO
• Used for special purpose computing problems
• Not used by large numbers of programmers mostly
  used by specialists
• Customized to do one thing very well

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Compilers

• Compilers are really translators
• Translate very abstract languages into more
  specific directions to the machine
• Because they try to be general purpose they can
  insert extra steps that arent really needed
  code bloat
• Use two passes when reading the code
• Pass 1 Find all the names in the code (variables
  and labels)

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Compilers II

• Then a table is made for each name
• Second pass uses the table made in pass 1 and
  translates the code with the location of the name
  in the table in mind
• Compilers are made for a language and a target
  computer

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Languages

• Interpreted
• BASIC
• FORTH
• HTML
• Structured/Functional
• C
• Pascal
• OO
• C
• Java

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Languages II

• 5th Generation
• Prolog
• Haskel

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Coding Examples - Microcode

• 11000010
• 00000000
• 00101000
• 00101100
• 11000100
• 00000000
• 00101000
• 00110000
• 10000110
• 10001000

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Coding Examples - Assembly

• ld r4,r5
• ba loop
• addcc r3,r5,r3
• jmpl r154,r0

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Coding Examples - HTML

• ltbodygt
• ltdiv idwelcomegt
• lth1gtWelcome to the CS101, Spring 2006
  Website!lt/h1gt
• lt/divgt
• ltmarquee scrolldelay"0"gt
• lt!-- Enter your marquee text here. To change the
  width of the marquee, edit it in the CSS --gt
• The Study Guide for Exam 1 is Linked in at the
  bottom of the page
• lt/marqueegt
• ltpgt
• ltbrgt
• lt/pgt
• lth1gtLecturelt/h1gt
• ltdiv idindent_5gt
• ltpgt
• lt!-- Enter the Lecture information here. To
  change indentation of paragraph, goto indent_5
  and edit the left property of the p section. --gt

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Coding Examples - C

• int main()
• int val 1
• int count 0
• int unicityu 7 //Upper bound for a unicity
  measurement, used to make it easier to run a loop
  past a float value (ie, rounding up)
• int k 25
• int a 26
• int max
• float s
• float rl .75
• float confidence 0
• double unicity
• int filecounter 0
• double intern, top, bottom, denom
• //Calculate unictiy
• // kfact(26)
• top log10(k)

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Coding Examples - Python

• z ins.read(1)
• print loop
• print tempcount
• print lettercount
• loop 0
• outs.write(inputfile)
• outs.write("\n")
• while(loop lt 26)
• print lettercountloop
• outs.write("d," (lettercountloop))
• loop loop 1
• print inputfile
• print lettercount
• ins.close
• outs.close
• print "File is written and this job is done."

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Coding Examples - Prolog

• get_attrs(Word,'adj',Ok)
• - get_quant(Word,Quant),
• stringlist_concat(Word,',',Quant,Attrs),
• file_data(adj,Attrs),
• write('Saving '),write(Word),write_ln(' as an
  adjective to permanent memory.'),
• retract(words(_)),
• make_word_list,
• Ok is 1.

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Coding Examples - Scripting

• echo Changing directories into 1
• echo Using input file 2 as the input file
• echo ....
• cd 1
• echo .....
• echo Checking all m-gram combinations
• c\dissertation\shiftandsubciphercfiles\debug\ma
  in -i 1\output35.txt
• c\test\release\tester -i 2 gtgt 1\output35.txt
• c\dissertation\shiftandsubciphercfiles\debug\ma
  in -i 1\output35.txt
• echo ....
• cd c\dissertation
• echo Complete

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Algorithms

• Algorithms are sometimes called methods
• Done step by step and in order the steps will be
  accomplished
• Specify things in detail
• Lets try an example
• Washing clothes
• Typically designed in pseudo code
• Can contain other algorithms

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Programs

• Typically written by programmers
• Contain one, or more algorithms
• Written in, or can be translated into, a language
  that is understood by the computer
• Usually stored for multiple uses
• Perform one job

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Program Attributes (Should be)

• Small as possible
• Portable
• Store as many as possible in memory
• As fast as possible
• Use as little memory as possible
• Easy to understand when read
• Well tested (get rid of the errors)

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Programs

• Several fields study software programs
• Software Engineering studies ways to make better
  programs
• Complexity studies how to make faster programs
  that use less memory
• Note that sometimes the goal of fast, small, and
  memory efficient are exclusive of each other and
  decisions have to be made

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Questions?