Function pointer type, function table, and interface theory notes (updated)

Function pointer definition:

Void (* point_fun) (const char * str );

Point_fun is first combined with * as a pointer and () as a function operator, so this pointer points to the Function

 

 

[Cpp]
# Include <stdio. h>
 
Void say_hello (const char * str );
Void (* point_say_hello) (const char * str); // point_say_hello is first combined with * as a pointer and () as a function operator, so this pointer points to the Function
 
Typedef void FUN (const char * str); // defines a FUN function type.
FUN say_typedef; // use the type definition defined above. FUN variables are equivalent to declaring a function.
FUN * point_say_typedef; // use the type definition defined above. The FUN type pointer is equivalent to defining a function pointer.
 
Void (* say_table [2]) (const char * str); // according to the sequence of operators, say_table is an array. The elements of an array are pointers to functions.
// Void (* say_table [2]) (const char * str) = {point_say_hello, point_say_typedef };
# Define say_interface (a) say_table [a] ("lang") // equivalent to the interface
 
Typedef void (* POINT_FUN) (const char * str); // defines the function pointer type of a POINT_FUN class.
POINT_FUN point_fun;
 
Void main (){
Printf ("lang start \ n ");
Point_say_hello = say_hello;
Point_say_hello ("langxw ");
 
Point_say_typedef = say_typedef;
Point_say_typedef ("langxw ");
 
Say_table [0] = point_say_hello;
Say_table [1] = point_say_typedef;
Say_interface (0 );
Say_interface (1 );

Point_fun = say_hello;
Point_fun ("point_fun ");
}
 
Void say_hello (const char * str ){
Printf ("hello % s \ n", str );
}
 
Void say_typedef (const char * str ){
Printf ("typedef % s \ n", str );
}

# Include <stdio. h>

Void say_hello (const char * str );
Void (* point_say_hello) (const char * str); // point_say_hello is first combined with * as a pointer and () as a function operator, so this pointer points to the Function

Typedef void FUN (const char * str); // defines a FUN function type.
FUN say_typedef; // use the type definition defined above. FUN variables are equivalent to declaring a function.
FUN * point_say_typedef; // use the type definition defined above. The FUN type pointer is equivalent to defining a function pointer.

Void (* say_table [2]) (const char * str); // according to the sequence of operators, say_table is an array. The elements of an array are pointers to functions.
// Void (* say_table [2]) (const char * str) = {point_say_hello, point_say_typedef };
# Define say_interface (a) say_table [a] ("lang") // equivalent to the interface

Typedef void (* POINT_FUN) (const char * str); // defines the function pointer type of a POINT_FUN class.
POINT_FUN point_fun;

Void main (){
Printf ("lang start \ n ");
Point_say_hello = say_hello;
Point_say_hello ("langxw ");

Point_say_typedef = say_typedef;
Point_say_typedef ("langxw ");

Say_table [0] = point_say_hello;
Say_table [1] = point_say_typedef;
Say_interface (0 );
Say_interface (1 );
 
Point_fun = say_hello;
Point_fun ("point_fun ");
}

Void say_hello (const char * str ){
Printf ("hello % s \ n", str );
}

Void say_typedef (const char * str ){
Printf ("typedef % s \ n", str );
}

 

 

End