1. The document discusses various input/output functions in C including printf(), scanf(), putchar(), gets(), and puts(). It provides examples of using format specifiers like %d, %f, %c with printf and scanf. 2. Functions like putchar() and gets() are used to output/input single characters and strings. Examples demonstrate using gets() to accept user input and puts() to output strings. 3. The last section provides more complex examples combining multiple functions like printf(), scanf(), gets() to perform input/output operations and manipulate strings.

2. 1.

Preprocessing Directive
#include <stdio.h>
stdio.h
preprocessing directives

3. 
2
- #include <
>
include)
- #include “
”

4. 2.

main( )
main “
”
{
}
{
} main( )
void main(void)
main()

6. 3.

comment)
source code
2
•

10. Run >
Run < Ctrl + F9> )
LampangKanlayanee School
printf( )
String)
;)
stdio ( standard
input output)
#include directive) stdio.h
header file)

11. 
: printf()
printf()
intprintf (<control>, <argument list>);

12. printf()
(Statements)
argument list
1
(,)
control “
” 2

13. 
%c
%s
% d
% u
% f
% e e
%x
%o

14.  1.1
printf()
intmain( )
{ intsum=3;
printf(“ The sum is %d ”,sum);
return 0;
}
The sum is 3

15.  1.2
printf() %d %u
intmain( )
{ intnum = -3, tot = 5;
printf(“num = %d tot = %u ”,num,tot);
return 0;
}
num = -3 tot = 5

16. 1.3 printf()
%f %e 2
intmain( )
{ floatnum = 22.75;
printf(“ %.2fn%.2e ”,num,num);
return 0;
}
22.75
2.28e+01

17.  printf ( )
printf( )
print format

18. 
%d
%u
%f
%c 1
%s
1

19. 
n
t tab 8
a
Backslash

20. 
printf( )

21. 5 + 5 = 10
printf( ) string format

22. Hello word
3 2
data list

24. 
printf( )
string format
““
data list ““
printf( )
• d 2
• d a
• s b

25. 
f)
printf( )
f

27. 
6
printf( ) n)
printf( )
printf( )
n)
printf( )

28.  : scanf()
intscanf (<control>, <argument list>);
intscanf (<control>,
<argument list>);
scanf()
(key board)

29. argument list
(,)
&
control
“”
printf

30.  2.1 scanf
intmain( )
{ intnum;
scanf( “ %d ”,&num);
return 0;
}
1
num

31. 2.2 scanf
intmain( )
{ intnum; charch;
scanf( “ %c ”,&ch);
scanf( “ %d ” ,&num);
printf(“ %d %c ” ,num, ch);
return 0;
}
2
1
num
1

32.  : expression
var = expression ;
var = expression ;
var
Expression

33.  : expression
var = expression ;
var = expression ;
var
Expression

34. 
sum = a b ;
a
b
sum

37.  –
putchar()
putchar()
intputchar (<character>);
putchar()
(Statements)

38. 1.4 putchar()
intmain( )
{ inta=65;
putchar(a);
putchar(„a‟);
return 0;
}
Aa

39. 2 getchar ( )
getchar ( )
1
enter
getchar ( );
getchar ( );

42. 3 getch ( )
getch ( )
1
enter
getch ( );

45. 4 getche ( )
getche ( )
1
enter
getche ( );

48.  3. –
3.1
#include <stdio.h>
intmain(){
intx_value = 9;
printf("x = %dn",x_value);
return0;
}

49.  3.2
#include <stdio.h>
intmain(){
intx,y,sum;
x = 7; y = 2;
sum = x + y;
printf("Total = %dn",sum);
return0;
}

50.  3.3
#include <stdio.h>
intmain(){
int x, y;
x = 7; y = 4;
--x; ++y;
printf("x = %2dn",x);
printf("y = %6dn",y);
return0;
}

51.  3.4
#include <stdio.h>
intmain(){
int profits, employees;
profits = 9; employees = 2 ;
printf("Each employee gets %.2f",
(float) profits/employees);
return0;
}

52.  3.5
include<stdio.h>
intmain(){
charany_char;
printf("Please type a character: ");
scanf("c%",&any_char);
printf("Thank you, your character are
%c",any_char);
return0;
}

53.  3.6
#include <stdio.h>
int main(){
printf("n****Using .1f****n");
printf("%.1f%.1f%.1fn", 4.0, 16.5, 589.3);
printf("%.1f%.1f%.1f", 400.0, 1600.5, 58900.3);
printf("nn****Using 8.1f****n");
printf("%8.1f%8.1f%8.1fn", 4.0, 16.5, 589.3);
printf("%8.1f%8.1f%8.1f", 400.0, 1600.5, 58900.3);
printf("%-8.1f%-8.1f%-8.1fn", 4.0, 16.5, 589.3);
printf("%-8.1f%-8.1f%-8.1f", 400.0, 1600.5,
58900.3);
return 0;
}

54.  3.7
#include <stdio.h>
int main(){
printf("n");
printf("xC9xCDxBBn");
printf("xC8xCDxBCn");
return 0;
}

55.  3.8
#include <stdio.h>
#include <ctype.h>
intmain(){
charany_char;
printf("Please type a lowercase letter:");
scanf("%c", &any_char);
if(any_char>= 'a')
printf("In uppercase: %c n",
toupper(any_char));
return0;
}

56.  –
string
char [ n ]
put
puts string_argument ;
string_argument

59. 
-
word
Char word [15] = * Example * ;
-
puts
puts word ;
puts ;

60.  gets
enter
gets
gets ; ;
string_var = get ;
string_var = get ;

63. 
-
enter
gets word ;
-
-printf you name is %s n ,
word ;

64. 