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We shall review your impudence at a later date

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We shall review your impudence at a later date

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    1. “We shall review your impudence at a later date…” David Niven in “Around the World in 80 Days” (1956)

    2. Computer Science 101 Lecture 19 Spring Semester 2008 Friday, February 29 Week 7/18 Albert H. Carlson

    3. 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.

    4. 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

    5. 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 aren’t really needed – “code bloat” Use two passes when reading the code Pass 1: Find all the names in the code (variables and labels)

    6. 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

    7. Languages Interpreted BASIC FORTH HTML Structured/Functional C Pascal OO C++ Java

    8. Languages II 5th Generation Prolog Haskel

    9. Coding Examples - Microcode 11000010 00000000 00101000 00101100 11000100 00000000 00101000 00110000 10000110 10001000

    10. Coding Examples - Assembly ld %r4,%r5 ba loop addcc %r3,%r5,%r3 jmpl %r15+4,%r0

    11. Coding Examples - HTML <body> <div id=welcome> <h1>Welcome to the CS101, Spring 2006 Website!</h1> </div> <marquee scrolldelay="0"> <!-- Enter your marquee text here. To change the width of the marquee, edit it in the CSS --> The Study Guide for Exam 1 is Linked in at the bottom of the page </marquee> <p> <br> </p> <h1>Lecture</h1> <div id=indent_5> <p> <!-- Enter the Lecture information here. To change indentation of paragraph, goto #indent_5 and edit the left property of the p section. --> Sections 1 - 3 have lecture at 12:30 - 12:20 in 222 TLC <br> Sections 4 - 6 have lecture at 2:30 - 3:30 in 222 TLC </p>

    12. 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 // k=fact(26); top = log10(k); // cout << top << endl; bottom = (rl*log10(a)); unicity = top/bottom; cout << "Calculated unicity distance is as follows:\n"; cout << unicity << " = " << top << "/" << bottom << endl << endl << endl; unicityu = unicity+10; // cout << k << endl; for(count=0;count<26;count++) { key[count]=0; singkey[count]=0; dikey1[count]=0; dikey2[count]=0;

    13. Coding Examples - Python z = ins.read(1) # print loop # print tempcount # print lettercount loop = 0 outs.write(inputfile) outs.write("\n") while(loop < 26): # print lettercount[loop] outs.write("%d," % (lettercount[loop])) loop = loop + 1 print inputfile print lettercount ins.close outs.close print "File is written and this job is done."

    14. 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.

    15. 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\shiftandsubcipherc++files\debug\main -i %1\output35.txt c:\test\release\tester -i %2 >> %1\output35.txt c:\dissertation\shiftandsubcipherc++files\debug\main -i %1\output35.txt echo .... cd c:\dissertation echo Complete

    16. 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

    17. 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

    18. 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)

    19. 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

    20. Questions?

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