??T3122/106 G??ssa p????a

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??T3122/106G??ssa p????aµµat?sµ??

• S??a?t?se??

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???????µ?? / ??????µµata

• ?????µe ??a p??ß??µa e?te???ta? µ?a a???????a ap?
  e?t???? se s???e???µ??? se???
• ???????µ?? ?a?????e? t?? e?t???? ?a? t? se???
  e?t??es??
• ??e???? p?????µµat?? (program control) ?a?????e?
  a?st??? t? se??? e?t??es?? t?? e?t????

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S??a?t?se?? - Functions

• ???????µe t? p????aµµa se µ???
• F???s?f?a t?? d?a??e? ?a? ßas??e?e (divide and
  conquer)
• ?a µ??? a?t?st?????? se ep?µ????? ?a? µ????te?a
  p??ß??µata
• ??a????a µe µ?a ep??e???s?
• ? p???st?µe??? a?a??te? µ?a d???e?? se ??p????
  ?f?st?µe??
• ?a???e? t? ap?t??esµa ????? ?a e?d?af??eta? ??a
  t?? ?ept?µ??e?e?
• ?a?e????e?e?

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S??a?t?se?? - Functions

• ?a ?p?p??ß??µata p?? e????a d?a?e???s?µa
• ???e ?p?p??ß??µa a?t?st???e? se µ?a s????t?s?
• ??? e????? d?a?e???s? ??d??a
• Debugging
• Updating
• ???s? ?pa????t?? s??a?t?se?? se ?a??????a
  p?????µµata ??a t? ??s? ???? p??ß??µ?t?? code
  reuse
• ?pa?a???s?µ?p???s? ??d??a
• ?p?f??? epa??????? t?? ?d??? ??d??a
• ?fa??es? / abstraction ???ß??ta? ?ept?µ??e?e?
  p?? de? e??a? apa?a?t?te? s??e??? st??
  p????aµµat?st?

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S??a?t?se?? - Functions

• Updating
• Code reuse

main()
S??a?t?s?a??? ?????aµµat?sµ??
main()
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??µ?µ???? p????aµµat?sµ??

• O?????s? t?? p?????µµat?? se s??a?t?se??
  ap??p???s? t?? ??d??a
• ep??e?t????µaste se ap???ste?e? d?ad??as?e?
• a?t???µ? ???p???s?, d?????s? ?a? ße?t?st?p???s?
  tµ?µ?t?? t?? ??d??a, a?e???t?ta ap? t? ?p????p?
  p????aµµa
• ?a ???s?µ?p??e?ta? ap? eµ?? ? ?????? se
  d?af??et??? p?????µµata.
• ?ta? ?p???e? ap?µ???s? t?? ??d??a se a?t???µ?
  s????t?s?, ? ???s? t?? ap??p??e?ta? s?µa?t???
  ?a??? µa? apas???e? µ??? t? p?? t?? ?a???µe ?a?
  t? ???sµata p??pe? ?a pe??s??µe st? s????t?s?
  ?a? ??? t? p????? a???ß?? ?p?????sµ??? e?te?e?
  (µa??? ???t?).
• ? ??????s? t?? ??d??a se ded?µ??a ?a? se
  d?ad??as?e? p?? ep?d???? se a?t? pe?????feta? ??
  d?µ?µ???? (structured) ? d?ad??ast????
  (procedural) p????aµµat?sµ??.

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???sµ?? S??a?t?se??

• ???µa-s????t?s?? ?p???d?p?te de?t? ???µa
• ?p?st?ef?µe???-t?p?? t?p?? t?? ded?µ???? p??
  ep?st??fe? ? s????t?s?
• void de? ep?st??fe? t?p?ta
• ??sta-pa?aµ?t??? d???se?? pa?aµ?t???, ???????ta?
  µe ??µµa (t?p?? pa??µet???, t?p?? pa??µet???,
  ...)
• ?p?st?ef?µe???-t?p?? ???µa-s????t?s??
  (??sta-pa?aµ?t???)
• ????se?? µetaß??t??
• ??t????

int SquareIt(int a) int result result
aa return result
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???s? S??a?t?se?? Function Call

• ???µa_s????t?s?? ( ???sµa1, ..., ???sµa?)
• ??f?as?1 ? ???µa_s????t?s?? ( ??f?as?1 ...,
  ??f?as??)
• t?µ?1 ? ? t?µ? p?? ep?st??fe? ? ??d??a? t??
  s????t?s?? ?ta? e?te?este? µe ta d?sµ??a
  ???sµata
• t?p??1 ? ? t?p?? p?? ep?st??fe? ? s????t?s?
• x (SquareIt(5) gt 7)
• ? ??f?as? SquareIt(5)a?t??a??stata? ap? t??
  ??f?as? 25.

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S??a?t?se?? void

• ? ep?st?ef?µe??? t?p?? µp??e? ?a e??a? void.
  ?????eta? ?ts? ?t? de? ep?st??feta? t?µ?.
• ? ??sta ???sµ?t?? µp??e? ?a e??a? ?e?? ?,
  ?s?d??aµa, ?a pe????e? t? ???? void.
• void f(int x)
• printf(Test d\n,x)
• return
• ?????
• x f() 10

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???s?

• ?? ???µ? t??, µ?sa se ?e???? pa?e??se??, ap?
  p?s?t?te? ?at??????? t?p?? ?ste ?a a?t?st??????
  sta ???sµat? t??, ? ?a µp????? ?a µetat?ap??? se
  a?t?.
• (G?a t??a) ?? p?s?t?te? a?t?? p?epe? ?a e??a?
  a???ß?? t?se? ?sa ?a? ta ???sµata.

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Call by value

• ??t???af? t?? t?µ?? t?? ???sµat?? pe???e? st?
  s????t?s?
• ???a??? st? ???sµa (a?t???af?) de? ep??e????? t?
  p??t?t?p?
• ???s? ?ta? ? s????t?s? ??? ??e???eta? ?a a????e?
  t? ???sµa
• ?p?fe????µe a??a??? ?at? ?????

/?p?st??fe? t? µ???st? µeta?? t?? x, y/ int
max(int x,int y) int z x /d???se??
µetaß??t??/ if (y gt x) /??sta e?t????/
z y return z
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Call by value

• ???s?µ? st? d?µ?µ??? p????aµµat?sµ? ?a???µe µ?a
  s????t?s? ????? t?? ???d??? ?a µa? a????e? t??
  t?µ?? t?? µetaß??t?? µa?
• ??d????? ?a p??pe? ?a t? ?aµß????µe ???e f??? ?p
  ????

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???S??OS
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Call by reference

• T????µe ?a a??????µe t?µ? sta ???sµata t??
  s????t?s??
• ?e???µe t? d?e????s? t?? µetaß??t??
• ????e???µe p??? sta ?d?a ta ded?µ??a ?a? ???
  sta a?t???afa t???
• ???pe? ?a ?aµß????µe ?p ???? t?? ep?d?as? t??
  s?et???? ???se??

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??? t?? ??????µµat??

• ? ??? t?? p?????µµat?? a????e? ?ta? s??a?t?se?
  t?? ???s? µ?a? s????t?s??
• f(a, b, c)
• ???ta ?p????????ta? ?? e?f??se?? p?? a?t?st??????
  sta ???sµata
• ?? t?µ?? t?? e?f??se?? a, b, c a?t????f??ta? sta
  ???sµata t?? f µe t?? ?d?a se???
• ? ??e???? µetap?d? st?? p??t? e?t??? t?? f
• ?? e?t???? t?? f e?te????ta? µ???? ?a s??a?t??e?
• return ??f?as?
• ????? s????t?s?? (d??ad? )
• ? ???s? f(a, b, c) a?t??a??stata? µe t??
  ep?st?ef?µe?? t?µ?

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S??a?t?se?? ß?ß????????

• S??a?t?se?? ???sµ??e? ap? t? ???st? (user defined
  functions)
• S??a?t?se?? ß?ß???????? (library functions)
• ? t?p??? ß?ß??????? t?? C
• ß?ß??????e? s??a?t?se?? st? d?ad??t??

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? ß?ß??????? ltmath.hgt

• double sqrt(double x) ?p??????e? t??
  tet?a?????? ???a t?? x, p??pe? x gt 0
• double exp(double x) ?p??????e? t?? e??et???
  t?? x, ex
• double log(double x) ?p??????e? t?? f?s???
  ???????µ? t?? x, ln(x)
• int abs(int val) ?p??????e? t?? ap???t? t?µ?
  t?? val
• double pow(double x, double y)  ?p??????e? t??
  t?µ? t?? x ???µ??? st? d??aµ? y, ?y
• double sin(double x) ?p??????e? t? sine t?? x,
  se rad
• double cos(double x) ?p??????e? t? cosine t??
  x, se rad
• double tan(double x) ?p??????e? t?? efapt?µ???
  t?? x, se rad
• double fmod(double x, double y) ?p??????e? t?
  de?ad??? ?p????p? t?? d?a??es?? ?/y, y gt 0.
• double ceil(double x) ?p??????e? t?? µ????te??
  a???a?a t?µ? ??? µ????te?? ap? x.
• double floor(double x) ?p??????e? t??
  µe?a??te?? a???a?a t?µ? ??? µe?a??te?? ap? ?.

G?a ?a ?????µe compile p????aµµa p?? ???s?µ?p??e?
t?? math.h gtgcc lm program.c
include ltstdlib.hgt int rand(void) void
srand(unsigned int seed) ? s????t?s? rand
ep?st??fe? ?e?d?t??a???? a???µ??? ap? 0 ???
RAND_MAX ? s????t?s? srand ???s?µ?p??e?ta? ??a
t?? a?????p???s? t?? rand() ?a? t? ?????s?
?e?d?t??a??? a???µ??. ?a???µe µ?a f??? t??
srand ?a? µet? t?? rand d?ad????? ??a t??
pa?a???? t?? t??a??? a???µ??. ?? ?a?a?a??s??µe
t?? srand ?a? µet? t?? rand ?a p???a??s??µe t??
?d?a se??? t??a??? a???µ??.
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???sµ?? S??a?t?se??

• ????se?? µetaß??t?? µ?sa se blocks ??????S
  µetaß??t??
• S??a?t?se?? ??? µp????? ?a ???st??? µ?sa se ???e?
  s??a?t?se??
• ??????????? s????t?s? µp??e? ?a ?a??se? ???e?
  s??a?t?se?? ?a? t?? ea?t? t?? (a?ad??µ?)

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???t?t?pa S??a?t?se?? (Function Prototypes)

• ?p?st?ef?µe???-t?p?? ???µa-s????t?s?? (??sta
  t?p??-pa?aµ?t???)
• (???-) ????se?? t?? s??a?t?se?? st?? a??? t??
  a??e???
• ??e???eta? a? ???s?µ?p????µe t? s????t?s? p???
  t?? ???sµ? t??
• ??e??e?t?µata
• ???????µe t?? ???? ???s? t?? s??a?t?se?? (p???
  a??µ? t?? ???p???s??µe)
• ?p????µe ?a d??µe p??e? e??a? ?? s??a?t?se?? p??
  ????? ???p????e? st? p????aµµa
• ?p????µe ?a ?a??s??µe ??e? t?? s??a?t?se?? p??
  ????? ???p????e? st? p????aµµa ????? ?a µa?
  e?d?af??e? ? se??? p?? ????? ??afte?

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• 1. Function prototype (3 parameters)
• 2. Input values
• 2.1 Call function
• Function definition
• Program Output

Enter three integers 22 85 17 Maximum is 85
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S??a?t?se??

• ?p????????a µe t? ?p????p? p????aµµa
• ?????ta? ???sµata
• ?p?st??f??? µ?a t?µ?
• ?p?µ??????? t?? ep???s? t?? ?p?p??ß??µat??
• ?da????, de? ?????µe ?aµ?a ???? ep?d?as? st?
  ?p????p? p????aµµa p??a? t?? pa?ap???
• S??a?t?s?a??? p????aµµat?sµ?? (functional
  programming)
• ??d??eta? ?a ep??e?s??? ?? a????? t? p????aµµ?
  µa? a? ???s?µ?p????µe ?a??????? µetaß??t??,
  de??te?, ?t?
• ?a?e????e?e?

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S??a?t?se?? ?a? ?etaß??t??

• ?d??t?te? µetaß??t??
• ?µß??e?a (scope)
• ???a µ??? t?? p?????µµat?? a?a????????? t?? ?d?a
  µetaß??t? (?d?a ??s? µ??µ??) µe t? ?d?? ???µa
• ?????e?a ?pa???? st? µ??µ? (storage duration)
• ??te µ?a s???e???µ??? d?e????s? µ??µ?? ?aµß??e?
  ??a s???e???µ??? ???µa ?a? p?te ap?desµe?eta?
  a?t? ? a?t?st????s?
• ???? t? pa??? ?a a????s??µe t?? pe??pt?s? ?a
  ????µe ????se? t? p????aµµa se d?af??et??? a??e?a

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?µß??e?a

• ??a µetaß??t? µp??e? ?a ??e? eµß??e?a
• ?a?????? se ??? t? p????aµµa e??? a??e???
• ??p??? µ?sa st?? ???sµ? µ?a? s????t?s??
• ??p??? µ?sa se ??a block

• int foobar
• int
• fun()
• int i, foo
• int bar
• for (i0iltNi)
• int bar

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?a??????? (global) µetaß??t??

• ???????ta? (s?????? p??? ?a?) ??? ap? ???e
  s????t?s?
• int global1, global2
• int main(void)
• global1 5
• ?µß??e?a p??spe??s?µe? ap? ???e ???? s????t?s?
  µet? t?? d???s? t???
• ?????e?a ?pa???? ap? t?? a??? t?? e?t??es??
  µ???? t? t???? ???? t?? p?????µµat??

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?a??????? (global) µetaß??t??

• ???s?µe? ?ta? p????? s??a?t?se?? µ???????ta?
  ????? ded?µ??a
• de? e??a? p?a?t??? ?a ta pe???µe ?? ???sµata ???e
  f???
• ? ???s? µ?a? s????t?s?? µp??e? ?a a????e? t??
  ?at?stas? ?a? ??a t?? ?p????pe?.
• ??s???? ?aµ?? f??? ?a ßeßa??s??µe ?t? ?? a??a???
  ?a ?????? µe s?st? se???
• ???pe? ?a ?aµß????µe ?p ???? p????? pe??pt?se??
  ta?t?????a
• ??s???? ? epa?a???s?µ?p???s? t??p?p???s? t??
  p?????µµat??
• ???F?G??? t?? ?a??????? µetaß??t?? a? de? e??a?
  apa?a?t?te?!

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??p???? (local) ?etaß??t??

• ????s? µ?sa se µ?a s????t?s?/block
• int main(void)
• int local1, local2
• local1 5
• int local3
• local3 7
• ?µß??e?a p??spe??s?µe? µ??? µ?sa st? ?d?a
  s????t?s?/block
• ?????e?a ap? t?? a??? µ???? t? t???? t??
  e?t??es?? t?? s????t?s??/block

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??p???? (local) µetaß??t??

• ???s?µe? ??a t?? pe??ss?te?e? pe??pt?se??
• S?????? ?????µe µetaß??t?? ??a ap????e?s?
  e?d??µes?? ap?te?esµ?t??. ?? te?????
  ?p?????sµ?? ?ata?????? s?????? se µ?a t?µ?, a?t??
  p?? ep?st??fe? ? s????t?s?
• ???spa??ste ?a ???s?µ?p??e?te µ??? t?p????
  µetaß??t?? ?a? ?a s??fteste ??se?? p?? de?
  ???s?µ?p????? ?a??????? µetaß??t??
• ???s?µ? st? d?µ?s? t?? p?????µµat?? µe ap???
  s??a?t?se??

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?etaß??t??

• ?a??????? (global) ??a?t? t?p???? µetaß??t??
  (local)
• double sum //?a???????
• int nextOfX(int x)
• int y x //t?p???
• y y 1
• sum sum1
• return y
• main()
• int x 0 //t?p???
• sum 0
• x nextOfX(0)
• x nextOfX(x)

?p?????? ?s? t???e? ? s????t?s?
?p?????? ?s? t???e? t? p????aµµa