/* This program was originally written in C++  i */
/* hopefully this is properly translated into C */

/* from: http://www.newty.de/fpt/intro.html   */
/*------------------------------------------------------------------------------------   */
/* 1.2 Introductory Example or How to Replace a Switch-Statement   */
/* Task: Perform one of the four basic arithmetic operations specified by the   */
/*       characters '+', '-', '*' or '/'.   */

#include <stdio.h>


/* The four arithmetic operations ... one of these functions is selected   */
/* at runtime with a switch or a function pointer   */
float Plus    (float a, float b) { return a+b; }
float Minus   (float a, float b) { return a-b; }
float Multiply(float a, float b) { return a*b; }
float Divide  (float a, float b) { return a/b; }


/* Solution with a switch-statement - <opCode> specifies which operation to execute   */
void Switch(float a, float b, char opCode)
{
   float result;

   /* execute operation   */
   switch(opCode)
   {
      case '+' : result = Plus     (a, b); break;
      case '-' : result = Minus    (a, b); break;
      case '*' : result = Multiply (a, b); break;
      case '/' : result = Divide   (a, b); break;
   }

   printf ("Switch: 2+5= %f\n", result);
}


/* Solution with a function pointer - <pt2Func> is a function pointer and points to   */
/* a function which takes two floats and returns a float. The function pointer   */
/* "specifies" which operation shall be executed.   */
void Switch_With_Function_Pointer(float a, float b, float (*pt2Func)(float, float))
{
   float result = pt2Func(a, b);    /* call using function pointer   */

   printf ("Switch replaced by function pointer: 2-5= %f\n", result);
}


/* Execute example code   */
int main ()
{
   /* for third parameter: '+' specifies function 'Plus' to be executed */ 
   Switch(2, 5, '+');                        

   /* for third parameter: pointer to function 'Minus' */ 
   Switch_With_Function_Pointer(2, 5, Minus); 
}