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typedef
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typedef char C; //C cå³char c
typedef char field [50]; //field så³char[50]
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union
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union mix_t
{
long l;
struct
{
short hi;
short lo;
}s;
char c[4];
}mix;
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struct
{
char title[50];
char author[50];
union
{
float dollars;
int rmbs;
} price;
} book;
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struct
{
char title[50];
char author[50];
union
{
float dollars;
int rmbs;
};
} book;
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enum
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enum days{Mon, Tue, Wed, Thur, Fri, Sat, Sun};
days today = Mon;
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enum days{Mon=1, Tue, Wed, Thur, Fri, Sat, Sun};
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enum days{Mon, Tue=2, Wed};ãã//0 2 3
cout << Mon << endl;ãã//è¾åº0èä¸æ¯1
typedef
typedefåªæ¯ç¨äºéå½åä¸ç§å·²æçæ°æ®ç±»åã
typedef char C; //C cå³char c
typedef char field [50]; //field så³char[50]
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union
unionä¸çæ¯ä¸ªæåå ±äº«åä¸æ®µå åï¼æ¯ä¸ªæåçèµ·å§å åä½ç½®é½æ¯ä¸æ ·çï¼ï¼æ´ä¸ªunionç大å°åå³äºæé¿çæåç大å°ã
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union mix_t
{
long l;
struct
{
short hi;
short lo;
}s;
char c[4];
}mix;
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è¿ä¸ªunionçå å示æå¾å¦å¾ä¸æ示ï¼æ³¨æ32ä½æºå¨ä¸ï¼char为1byteï¼short为2bytesï¼long为4bytesï¼
å¿åunion
éå¿åunionï¼unionçåå为priceï¼
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struct
{
char title[50];
char author[50];
union
{
float dollars;
int rmbs;
} price;
} book;
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å¿åunionï¼union没æååï¼
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struct
{
char title[50];
char author[50];
union
{
float dollars;
int rmbs;
};
} book;
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enum
æ举类åï¼å ¶ä¸æ举å¼æ¯å¸¸éï¼èä¸æ¯åéã
enum days{Mon, Tue, Wed, Thur, Fri, Sat, Sun};
days today = Mon;
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enum days{Mon=1, Tue, Wed, Thur, Fri, Sat, Sun};
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enum days{Mon, Tue=2, Wed};ãã//0 2 3
cout << Mon << endl;ãã//è¾åº0èä¸æ¯1
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