Keyword Typedef in C

This guide covers keyword typedef in c with practical context and easy-to-follow details. Use it to understand the subject and apply the information confidently.

 typedef unsigned char BYTE ; 

After defining this type, the BYTE identifier can be used as an abbreviation for Unsigned char Types, for example:

 BYTE b1 , b2 ; 

By convention, Uppercase letters Are used for these definitions to make it easier for users to remember, but you can use lower case letters as follows:

 typedef unsigned char byte ; 

You can also use Typedef To provide a name for the user defined data type. For example, you can use typedef with A structure To define a new data type and then use that data type to define structure variables directly as follows:

 #include #include typedef struct Books { char tieude [ 50 ]; char tacgia [ 50 ]; char chude [ 100 ]; int id ; } Book ; int main ( ) { Book book ; strcpy ( book . tieude , "Lap trinh C" ); strcpy ( book . tacgia , "Pham Van At" ); strcpy ( book . chude , "Ngon ngu lap trinh C" ); book . id = 1234567 ; printf ( "Tieu de: %sn" , book . tieude ); printf ( "Tac gia: %sn" , book . tacgia ); printf ( "Chu de: %sn" , book . chude ); printf ( "ID: %dn" , book . id ); printf ( "n===========================n" ); printf ( "QTM chuc cac ban hoc tot! n" ); return 0 ; } 

Compiling and running the above C program will result:

Typedef Vs #Define in C

#define Is a directive in C which is also used to define aliases (abbreviations) for diverse data types similar to Typedef But there are the following differences:

The typedef Is limited to providing abbreviations for types only, while #define Can be used to define nicknames for both values, as you can define 1 as ONE, .

The Typedef Translation is performed by the compiler, while the #define Command is processed by the preprocessor.

Here is the simplest use of #define :

 #include #define TRUE 1 #define FALSE 0 int main ( ) { printf ( "Gia tri TRUE tuong duong: %dn" , TRUE ); printf ( "Gia tri FALSE tuong duong: %dn" , FALSE ); printf ( "n===========================n" ); printf ( "QTM chuc cac ban hoc tot! n" ); return 0 ; } 

Compiling and running the above C program will result:

According to Tutorialspoint

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