Scope of typedef and define

typedef :

If it is placed outside all functions, its scope is from the beginning of its definition until the end of the file;

If placed within a function, the defined field is defined from the beginning of the definition until the end of the function;

#define :

Scopes are defined from the beginning of the definition to the end of the entire file, whether within a function or outside of all functions.

Such as:

typedef ...//Start here to end of file

#define ...//start here to end of file

int negate (int num)

{

...

typedef ...//Start here to the end of the function. Note that in this function, before this definition, it cannot be used

#define ...//start here to end of file

...

}

typedef ...//Start here to end of file

#define ...//start here to end of file

void Show ()

{

typedef ...//Start here to the end of the function.

#define ...//start here to end of file

}

...

Summarize:

(1) Whether it is a typedef or a define, it cannot be used before the definition;

(2) the typedef is affected by the function range, and the define is not affected;

(3) whether it's a typedef or define ? , its scope does not extend to other files, even different files of the same program, and cannot be used with each other.

Scope of typedef and define