1. 15
18
19
31
37
38
39
6/2
1 2555

3. 1
6
7
8
9

4. 10
21
22
Mild Mapping
26
27

5. standard functions)
C h
eader file C h
header file
#include<header file.h>
C compiler
” library functions)

6. type int , float , char ,
double , void
void
int
function_name
type parameter parameter , N
parameter void
{
location variable declaration
statement_ ; statement_ ; ... statement_N
return(value);
void)
return
}

7. 1. User-defined
Function)
2. Standard Function)
include directives header
file
2
1.
2.
#include <stdio.h>
Main ()
{
Function-name2 ();
…………………...
Function-name1 ();
}
#include <stdio.h>
Main ()
{
Function-name1 ();

8. Function-name2 ();
…………………..
}
1.
#include
2.
()
void
function_name(void )

9. void function_name
(type_parameter parameter_name [,..] ) ;
function_ name
type_parameter
parameter_name
1 ,
#include <stdio.h>
Void addition (int , int ) ;
Void main ()
{
Int a,b ;
……....

10. Addition (a,b) ;
}
Void addition (int m , int n)
{
…............
}
Type_variable function_name parameter_name,… ;
Type_variable
function_name
parameter_name

11. variable_name = function_name();
variable_name
return (value)

12. (Local Variable)
(Global Variable)
(
)
/* 7th Sample Program: Local vs Global Variable */
#include<stdio.h>
int ans = 0;
int inc_one(int); /* function prototype */
void main()
{
int a = 3;
ans = inc_one(a);
printf(“Answer is %dn”, ans);
}
/* function definition: return x+1 */
int inc_one(int x)
{
int ans;
ans = x + 1;

13. return ans;
}
ans
(main)
ans
a
inc_one x ans
ans ans
inc_one ans
inc_one
ans
inc_one ans
ans

14. #vinclude
2.1
sinz x
: sin x x
Sin x ;
cos x
: cossine x x
cos x ;
tan x
: tangent x x
tan x ;

15. sqrt x
: 2 square root x x
sqrt x ;
pow x,y
: x y x 0
pow x ;
ceil x
:
ceil x ;
floor x
:
floor x ;
log x

16. : log n x x 0
log x ;
sinz x
: sin x x
Sin x ;
log10 x
: log 10 x
log10 x ;
exp x
: e e
2.718282 x e
exp x ;
fabs x

17. : x
fabs x ;
2.2
strcpy
: string2
m string1
Strcpy string1,
string2
strcat
:
string2 string1
strcat string1, string2
strcmp
:
Strcmp string1,
string2
strlen

18. :
Strlen string
strcmpi
:
- string1 string2 0
- string1 < string2 <0
- string1 > string2 >0
Strcmp string1, strin
g2
2.3
tolower
:
Tolower character
toupper
:
Toupper character

19. function_name
-
-

20. -

22. function_name
type_parameter
parameter_name

24. tolower

25. toupper

26. strcmp
rung
do
{
……………………….
} while (ans !=’n’) ;

27. -
-

28. printf
sin ()
#include

29. 6
1.
. type_variable function_name (parameter_name,…);
. type_variable function_none (parameter_name,…);
. variable function_name (parameter_name,…);
. type_variable function_name (parameter_,…);
2.type_variable
.
.
.
.

30. 3.function_name
.
.
.
.
4. 1
. void
. void
.
.
5.
. void function_name (type_parameter parameter_name[…]);
. void function_name (type_parameter parameter_name);
. void function_name (type_parameter parameter […]);

31. .
6.
.
.
.
.
7.
.5
.4
.3
.2
8.
.

32. .
.
.
9.
.
.
.
.
10.
.

33. .
.
.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

35. . 7 C
http://e-
learning.snru.ac.th/els/program lesson page _ html
21 2555.
http://uhost.rmutp.ac.t
h/kriengkri.l/w3.pdf 18 2555