recursion

1
????? 5 ????????
2
????????????

• ????????????????????????????????
• ???????????????????
• ?????????????????????????????????????????
• ???????????????????????????????????????
  (recursion)

3
????????????????

• ????????????????
• ???????????????
• ??????????????????????
• ?????????????????????????????
• ??????????????????????????????
• ??????????????????????????????

4
??????????????????
??????????????????? ??????????????????????????????
?????
Unstructured Programming
Procedural Programming
5
Unstructured Programming

• ?????? ?????????????????????????????????????????
  ????
• ??????? ???????????????????????????
  ?????????????????????????????????????????
• ???????????????,
• ???????????????????, ...

main program
6
????????5.1 unstructured programming
include ltstdio.hgt main() int first, second,
third printf(\n F(X) 3X 10 if X gt 0\n)
printf(\n F(X) 10 if X 0\n) printf(\n
Enter 3 values\n) scanf(d d d, first,
second, third) if (first gt 0)
printf(F(d) is d, first, 3first 10) else
printf(F(d) is 10, first) if (second gt
0) printf(F(d) is d, second, 3second
10) else printf(F(d) is 10, second) if
(third gt 0) printf(F(d) is d, third,
3third 10) else printf(F(d) is 10,
third)
Code program ???????
????? first
????? second
????? third
7
??????????????????? (????????????????????) ???
statement ???????????????????????????????????????
????????? copy ????????? ??????????????????????
????? statement ????????????????????? ????????????
??????????????????? ???????? Procedure
8
Procedural Programming (1/2)

• ?????? ??? statements ??????????????????????????
  ???????????? main ??????????? procedure call
  ???????????????? ??? statements ????
• ?????
• ???????????????????????????????????????
  ???????????? main ?????????????????????
• ??????????????????????????????????????????????????
  ???
• ?????????????????????????????????
  ????????????????? main ??????? procedures ??

9
Procedural Programming (2/2)

• ???????? main ??????????? procedure
  ?????????????????????????????????????????
  ??????????????? main ????????????????????????????
  procedures ??????????????????????????????
• ???? Procedural Programming ??????????????????????
  ???????????????? ???????? procedures ????????????

10
????????5.2 procedural programming
include ltstdio.hgt void get_Fx(int x) main()
int first, second, third printf(\n F(X) 3X
10 if X gt 0\n) printf(\n F(X) 10 if X
0\n) printf(\n Enter 3 values\n) scanf(d
d d, first, second, third)
get_Fx(first) get_Fx(second)
get_Fx(third) void get_Fx(int x) if (x gt
0) printf(F(d) is d, x, (3x) 10) else
printf(F(d) is 10, x)

• ????????????????????????????????
• ????????????????? x??????????????????????????

11
???????????????

• ???????? ???? Procedure ???
• ?????? statement ?????????????????????????
  ??????????????
• ??????????????????????????????????????????????

????
12
?????????????? C

• ??????????? C ????????????????????????? (main)
  ???????????
• ?????????????????????????????? statement
  ???????????
• ???? C ???????????????? 2 ???
• ????????????????? C
• ??????????????????????????????????

FUNCTIONS IN C
PROGRAMMER DEFINED FUNCTION
C STANDARD LIBRARY
13
C Standard Library

• ????????????????????????????????????????????? C
• ???????????????????????????
• disk I/O (input/output) ex. printf(), scanf(),
  
• string manipulation ex. strlen(), strcpy(),
• mathematics ex. sqrt(), sin(), cos(),
• etc..
• ??????????????????????? ???????????? include
  header file
• ???????????????????????? ????
• ????? printf(), scanf() ????????? include
  stdio.h
• ????? sqrt(), sin(), cos() ????????? include
  math.h
• etc.

14
???????? 5.3 ????????????????? C

• ????????????????????? ?????????????? sqrt() ??
  math.h
• ?????? double sqrt(double num)
• ???????????????
• include ltstdio.hgt
• include ltmath.hgt
• int main()
• printf(f, sqrt(16.0))

15
???????? 5.4

• ??????????? 10 ??????? 1 ??? 5 ???????????????????
  pow() ?? math.h
• ?????? double pow(double base, double exp)
• ?????? baseexp
• include ltstdio.hgt
• include ltmath.hgt
• int main()
• double x10.0, y 1.0
• do
• printf(f, pow(x,y))
• y
• while (y lt 6)

16
??????????????????????

• ????????????????????????????? 2 ???????
• ?????????????? (function prototype)
• ????????????? (function definition)
• ????????????????????????????????
  ??????????????????????????????????????????
• ???????????????????? main ????????????????????????
  ?????
• ???????????????????? main ????????????????????????
  ???????????????

17
????????5.5 ????????????????????????? 1
function prototype
function definition
18
????????5.6 ????????????????????????? 2