// ==========================================
// * Samples
// * Pointers to functions
// * Version 2.0
// ------------------------------------------
// * Language : C
// * Content  : Program file
// ------------------------------------------
// * Attachment
//   - pointers-to-functions.c
// ==========================================

 Alex Vinokur
     email: alex DOT vinokur AT gmail DOT com
     http://mathforum.org/library/view/10978.html
     http://sourceforge.net/users/alexvn

[ pointers-to-functions.c 2K ]
// ==========================================
// * Samples
// * Pointers to functions
// * Language : C
// * Version 2.0
// ==========================================

// ============ C-code: Begin ============

// --------------------------------------------------
char f1(int); // Declaration
char f1(int dummy) {return 'a';} // Implementation
char (*pf1) (int); // Variable

char *f2(int); // Declaration
char *f2(int dummy) { return (char*)0;} // Implementation
char *(*pf2)(int); // Variable

char (*f3(double)) (int); // Declaration
char (*f3(double d_dummy)) (int i_dummy) { return (char (*) (int))0;} // Implementation
char (*(*pf3)(double)) (int); // Variable
// --------------------------------------------------

// ===================================================================
// f1 is a 'function' that returns 'char' and takes an 'int-argument'.
// pf1 is a 'pointer-to-function'; the function returns 'char' and takes an 'int-argument'.

// f2 is a 'function' that returns 'pointer-to-char' and takes an 'int-argument'.
// pf2 is a 'pointer-to-function'; the function returns 'pointer-to-char' and takes an 'int-argument'.

// f3 is a 'function-1' that returns 'pointer-to-function-2' and takes a 'double-argument';
//         'function-2' returns 'char' and takes 'int-argument'.
// pf3 is a 'pointer-to-function-1'; the function-1 returns 'pointer-to-function-2' and takes a 'double-argument';
//         'function-2' returns 'char' and takes 'int-argument'.
// ===================================================================

// ---------------------------------------
typedef char (*pfunc_t1) (int);
typedef char *(*pfunc_t2) (int);
typedef char (*(*pfunc_t3)(double)) (int);
// ---------------------------------------

int main ()
{
char     ch;
char*    pch;

char (*pf4) (int);

pfunc_t1 pfunc1 = f1;
pfunc_t2 pfunc2 = f2;
pfunc_t3 pfunc3 = f3;
pfunc_t1 pfunc4;

  ch  = pf1 (1100);
  pch = pf2 (1200);
  pf4 = pf3 (1300.1);
  ch  = pf4 (1400);
  ch  = pf3 (1500.1)(1600);

  ch     = pfunc1 (2100);
  pch    = pfunc2 (2200);
  pfunc4 = pfunc3 (2300.1);
  ch     = pfunc4 (2400);
  ch     = pfunc3 (2500.1)(2600);

  return 0;