, 。 , 。 C 。 , 。
, , 。
:
enum weekday{sun,mon,tue,wed,thu,fri,sat};
enum weekday, 。 :
enum weekday day;
, 。 :
enum weekday{sun,mon,tue,wed,thu,fri,sat} day;
,sum,mon,…,sat , 。
。
① , , 。 , 。
② , ,C ,1,2,…。
,sun 0,mon 1,…sat 6,
day=mon;
day 1。 , 。 :
printf ("%d",day);
1。
, 。 :
enum weekday{sun=7,mon=1,tue,wed,thu,fri,sat}day;
,sun 7,mon 1, 1, sat 6 。
③ 。 :
if (day==mon) {…}
if (day>mon) {…}
: , , 0。 ,mon>sun,sat>fri。
C ?216?
④ , 。 :
day=(enum weekday)2;
, 2 day, workday=tue;
【 11.6】 , 。
# include
void main( )
{
enum weekday {sun,mon,tue,wed,thu,fri,sat} day;
int k;
printf("input a number(0--6)");
scanf("%d",&k);
day=(enum weekday)k;
switch(day)
{
case sun: printf("sunday/n");break;
case mon: printf("monday/n");break;
case tue: printf("tuesday/n");break;
case wed: printf("wednesday/n");break;
case thu: printf("thursday/n");break;
case fri: printf("friday/n");break;
case sat: printf("satday/n");break;
default: printf("input error/n");break;
}
}
:
input a number(0--6)1
monday
, , , :
printf(" %s",mon);
mon , 。
, , 。
------------------------------------------------------------------
: VC++ 6.0
, , #define , :
#define MON 1
#define TUE 2
#define WED 3
#define THU 4
#define FRI 5
#define SAT 6
#define SUN 7
, , 。 。
1. -
-
enum DAY
{
MON=1, TUE, WED, THU, FRI, SAT, SUN
};
(1) , ( ) , , 。
(2) DAY , , , 。
(3) 0, 1。
(4) , 。
(5) #define 。
(6) ; 。
2.
, 。 , : int, float, double, char, short 。 :
char a; // a char
char letter;
int x,
y,
z; // x,y z int
int number;
double m, n;
double result; // result double
, 。
:
enum DAY
{
MON=1, TUE, WED, THU, FRI, SAT, SUN
};
enum DAY yesterday;
enum DAY today;
enum DAY tomorrow; // tomorrow enum DAY
enum DAY good_day, bad_day; // good_day bad_day enum DAY
: :
enum // , DAY , 。
{
saturday,
sunday = 0,
monday,
tuesday,
wednesday,
thursday,
friday
} workday; // workday enum DAY
enum week { Mon=1, Tue, Wed, Thu, Fri Sat, Sun} days; // days enum week
enum BOOLEAN { false, true } end_flag, match_flag; //
: typedef , :
typedef enum workday
{
saturday,
sunday = 0,
monday,
tuesday,
wednesday,
thursday,
friday
} workday; // workday enum workday
workday today, tomorrow; // today tomorrow workday, enum workday
enum workday workday :
typedef enum
{
saturday,
sunday = 0,
monday,
tuesday,
wednesday,
thursday,
friday
} workday; // workday enum workday
workday today, tomorrow; // today tomorrow workday, enum workday
:
typedef enum workday
{
saturday,
sunday = 0,
monday,
tuesday,
wednesday,
thursday,
friday
};
workday today, tomorrow; // today tomorrow workday, enum workday
: , 。 :
:
typedef enum
{
wednesday,
thursday,
friday
} workday;
typedef enum WEEK
{
saturday,
sunday = 0,
monday,
} workday;
:
typedef enum
{
wednesday,
thursday,
friday
} workday_1;
typedef enum WEEK
{
wednesday,
sunday = 0,
monday,
} workday_2;
3.
3.1 。
:
: ,
#include
/* */
enum DAY { MON=1, TUE, WED, THU, FRI, SAT, SUN };
void main()
{
/* , */
int x, y, z;
x = 10;
y = 20;
z = 30;
/* , */
enum DAY yesterday, today, tomorrow;
yesterday = MON;
today = TUE;
tomorrow = WED;
printf("%d %d %d /n", yesterday, today, tomorrow);
}
:
#include
/* */
enum DAY { MON=1, TUE, WED, THU, FRI, SAT, SUN };
void main()
{
/* */
int x=10, y=20, z=30;
/* */
enum DAY yesterday = MON,
today = TUE,
tomorrow = WED;
printf("%d %d %d /n", yesterday, today, tomorrow);
}
: , 。
#include
/* , , */
enum DAY { MON=1, TUE, WED, THU, FRI, SAT, SUN } yesterday, today, tomorrow;
/* , */
int x, y, z;
void main()
{
/* */
x = 10; y = 20; z = 30;
/* */
yesterday = MON;
today = TUE;
tomorrow = WED;
printf("%d %d %d /n", x, y, z); // :10 20 30
printf("%d %d %d /n", yesterday, today, tomorrow); // :1 2 3
}
: , , 。
#include
/* , , 。 */
enum DAY
{
MON=1,
TUE,
WED,
THU,
FRI,
SAT,
SUN
}
yesterday = MON, today = TUE, tomorrow = WED;
/* , 。 */
int x = 10, y = 20, z = 30;
void main()
{
printf("%d %d %d /n", x, y, z); // :10 20 30
printf("%d %d %d /n", yesterday, today, tomorrow); // :1 2 3
}
3.2 , 。
#include
enum DAY { MON=1, TUE, WED, THU, FRI, SAT, SUN };
void main()
{
enum DAY yesterday, today, tomorrow;
yesterday = TUE;
today = (enum DAY) (yesterday + 1); //
tomorrow = (enum DAY) 30; //
//tomorrow = 3; //
printf("%d %d %d /n", yesterday, today, tomorrow); // :2 3 30
}
3.3
#include
enum
{
BELL = '/a',
BACKSPACE = '/b',
HTAB = '/t',
RETURN = '/r',
NEWLINE = '/n',
VTAB = '/v',
SPACE = ' '
};
enum BOOLEAN { FALSE = 0, TRUE } match_flag;
void main()
{
int index = 0;
int count_of_letter = 0;
int count_of_space = 0;
char str[] = "I'm Ely efod";
match_flag = FALSE;
for(; str[index] != '/0'; index++)
if( SPACE != str[index] )
count_of_letter++;
else
{
match_flag = (enum BOOLEAN) 1;
count_of_space++;
}
printf("%s %d times %c", match_flag ? "match" : "not match", count_of_space, NEWLINE);
printf("count of letters: %d %c%c", count_of_letter, NEWLINE, RETURN);
}
:
match 2 times
count of letters: 10
Press any key to continue
4. sizeof
#include
enum escapes
{
BELL = '/a',
BACKSPACE = '/b',
HTAB = '/t',
RETURN = '/r',
NEWLINE = '/n',
VTAB = '/v',
SPACE = ' '
};
enum BOOLEAN { FALSE = 0, TRUE } match_flag;
void main()
{
printf("%d bytes /n", sizeof(enum escapes)); //4 bytes
printf("%d bytes /n", sizeof(escapes)); //4 bytes
printf("%d bytes /n", sizeof(enum BOOLEAN)); //4 bytes
printf("%d bytes /n", sizeof(BOOLEAN)); //4 bytes
printf("%d bytes /n", sizeof(match_flag)); //4 bytes
printf("%d bytes /n", sizeof(SPACE)); //4 bytes
printf("%d bytes /n", sizeof(NEWLINE)); //4 bytes
printf("%d bytes /n", sizeof(FALSE)); //4 bytes
printf("%d bytes /n", sizeof(0)); //4 bytes
}
5.
#include
enum Season
{
spring, summer=100, fall=96, winter
};
typedef enum
{
Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday
}
Weekday;
void main()
{
/* Season */
printf("%d /n", spring); // 0
printf("%d, %c /n", summer, summer); // 100, d
printf("%d /n", fall+winter); // 193
Season mySeason=winter;
if(winter==mySeason)
printf("mySeason is winter /n"); // mySeason is winter
int x=100;
if(x==summer)
printf("x is equal to summer/n"); // x is equal to summer
printf("%d bytes/n", sizeof(spring)); // 4 bytes
/* Weekday */
printf("sizeof Weekday is: %d /n", sizeof(Weekday)); //sizeof Weekday is: 4
Weekday today = Saturday;
Weekday tomorrow;
if(today == Monday)
tomorrow = Tuesday;
else
tomorrow = (Weekday) (today + 1); //remember to convert from int to Weekday
}