使用枚举类型的变量

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使用枚举类型的变量

对枚举型的变量赋值

实例将枚举类型的赋值与基本数据类型的赋值进行了对比：

方法一：先声明变量，在对变量赋值

#include<stdio.h>   
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);

 }

方法二：声明变量的同时赋初值

#include <stdio.h>
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); 

}

方法三：定义类型的同时声明变量，然后对变量赋值。

#include <stdio.h>   
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); //输出：10 20 30 
printf("%d %d %d \n", yesterday, today, tomorrow); //输出：1 2 3

 }

方法四：类型定义，变量声明，赋初值同时进行。

#include <stdio.h>   
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); //输出：10 20 30 
printf("%d %d %d \n", yesterday, today, tomorrow); //输出：1 2 3

  }

对枚举型的变量赋整数值时，需要进行类型转换

#include <stdio.h>
  enum DAY { MON=1, TUE, WED, THU, FRI, SAT, SUN };  
void main() 
{

enum DAY yesterday, today, tomorrow;  
yesterday = TUE; 
today = (enum DAY) (yesterday + 1); //类型转换 
tomorrow = (enum DAY) 30; //类型转换 
//tomorrow = 3; //错误  
  printf("%d %d %d \n", yesterday, today, tomorrow); //输出：2 3 30 

}

使用枚举型变量

#include<stdio.h>
   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);
}

输出：

  match 2 times
  count of letters: 10 
Press any key to continue

枚举类型与sizeof运算符

#include<stdio.h>  
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 

}

综合举例

#include<stdio.h>
   enum Season //注意这里如果放在下面，后面就不能直接那样声明
 {

spring, summer=100, fall=96, winter 

};  
typedef enum
 { 

Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday 

} Weekday;  
void main() 
{   

printf("%d \n", spring); // 0 
printf("%d, %c \n", summer, summer); // 100, d 
printf("%d \n", fall+winter); // 193  
Season mySeason=winter;//就是这里，看上面的定义，也可以 enumSeason mySeason 
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       
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 

}

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