The document discusses enumeration types in C programming. Enumeration types allow defining symbolic constants to represent integer values. Several examples are provided to demonstrate defining enum types with symbolic names for colors like YELLOW, RED and BLUE. Enum variables can then be used in place of integer values in for loops and switch statements. Typedef is also shown to create alias names for enum types for improved readability and code organization.

1. Enumeration Types

2. 2
Enumeration Types
 Example
#include <stdio.h>
void main(void)
{
int color ;
for( color = 0 ; color <= 2 ; color++ ) {
switch( color ) {
case 0 : printf( “Yellown” ) ; break ;
case 1 : printf( “Redn” ) ; break ;
case 2 : printf( “Bluen” ) ; break ;
}
}
}

3. 3
Enumeration Types
 Example
#include <stdio.h>
#define YELLOW 0
#define RED 1
#define BLUE 2
void main(void)
{
int color ;
for( color = YELLOW ; color <= BLUE ; color++ ) {
switch( color ) {
case YELLOW : printf( “Yellown” ) ; break ;
case RED : printf( “Redn” ) ; break ;
case BLUE : printf( “Bluen” ) ; break ;
}
}
}

4. 4
Enumeration Types
 Example
#include <stdio.h>
#define YELLOW 0
#define RED 1
#define BLUE 2
#define Color int
void main(void)
{
Color color ;
for( color = YELLOW ; color <= BLUE ; color++ ) {
switch( color ) {
case YELLOW : printf( “Yellown” ) ; break ;
case RED : printf( “Redn” ) ; break ;
case BLUE : printf( “Bluen” ) ; break ;
}
}
}

5. 5
Enumeration Types
 enumeration Types
– Variables of enum type can be used in indexing expressions
and as operands of all arithmetic and relational operators
[Ex]
enum day { sun, mon, tue, wed, thu, fri, sat };
enum day d1, d2;
d1 = fri;
tag name
By default, the first element ‘sun’ is associated with 0.
The next element, mon, is associated with 1.
…
Define variables d1, d2 as type of enum ‘day’,
Assign a value of fri to d1

6. 6
Enumeration Types
 Example
#include <stdio.h>
enum color_type {Yellow, Red, Blue} ;
void main(void) {
enum color_type color ;
for( color = Yellow ; color <= Blue ; color++ ) {
switch( color ) {
case Yellow : printf( “Yellown” ) ; break ;
case Red : printf( “Redn” ) ; break ;
case Blue : printf( “Bluen” ) ; break ;
}
}
}

7. 7
typedef
 Example
#include <stdio.h>
enum color_type {Yellow, Red, Blue} ;
typedef enum color_type Color ;
void main(void) {
Color color ;
for( color = Yellow ; color <= Blue ; color++ ) {
switch( color ) {
case Yellow : printf( “Yellown” ) ; break ;
case Red : printf( “Redn” ) ; break ;
case Blue : printf( “Bluen” ) ; break ;
}
} }

8. 8
typedef
 Example
#include <stdio.h>
typedef enum {Yellow, Red, Blue} Color ;
void main(void) {
Color color ;
for( color = Yellow ; color <= Blue ; color++ ) {
switch( color ) {
case Yellow : printf( “Yellown” ) ; break ;
case Red : printf( “Redn” ) ; break ;
case Blue : printf( “Bluen” ) ; break ;
}
}
}

9. 9
Enumeration Types
 enumeration Types
[Ex]
enum day { sun=10, mon, tue, wed=24, thu, fri, sat=36 };
[Ex]
#define sun 10
#define mon 11
#define tue 12
#define wed 13
#define thu 24
#define fri 25
#define sat 36

10. 10
Enumeration Types
 Feature of enum type
– enum types are equivalent to integer type
[Ex]
int i;
enum { CLUBS, DIAMONDS, HEARTS, SPADES } s;
i = DIAMONDS; /* i = 1 */
s = 0; /* s = CLUBS */
s++; /* s = 1 */
i = s + 2; /* i =3 */