// file: lecture_29/example.cc
//
// local include files
//
#include "example.h"

// declare the main program
//
int main (int argc, char** argv) {

  // demonstate #define's
  //
  fprintf(stdout, STRING2, STRING1);

  fprintf(stdout, "exp1 = %d\n", EXPRESSION1);
  fprintf(stdout, "exp2 = %d\n", EXPRESSION2);

  // demonstrate macros
  //
  printf ("abs: %f\n", (float)ABS(atof(argv[1])));
  printf ("abs: %d\n", (long)ABS(atoi(argv[1])));
  printf ("max: %f\n", (float)MAX(atof(argv[1]), atof(argv[2])));
  printf ("max: %d\n", (long)MAX(atoi(argv[1]), atoi(argv[2])));
  printf ("biggest: %f\n", (float)BIGGEST(atof(argv[1]), atof(argv[2]),
					  atof(argv[3])));

  // declare an array of order 3 of doubles
  //
  int N = 3;
  double array[N];
  array[0] = 2.0;
  array[1] = 3.0;
  array[2] = 1.0;

  fprintf(stdout, "Before:\n");
  for (long i = 0; i < N; i++) {
    fprintf(stdout, "array[%d] = %f\n", i, array[i]);
  }

  // sort the array
  //
  qsort(array, N, sizeof(double), compare_doubles);

  // print out the sorted values
  //
  fprintf(stdout, "After:\n");
  for (long i = 0; i < N; i++) {
    fprintf(stdout, "array[%d] = %f\n", i, array[i]);
  }

  // declare an array of order 3 of strings
  //
  N = 3;
  char array2[N];
  array2[0] = (char)'a';
  array2[1] = (char)'Z';
  array2[2] = (char)'c';

  fprintf(stdout, "Before:\n");
  for (long i = 0; i < N; i++) {
    fprintf(stdout, "array[%d] = %c (%d)\n", i, array2[i], array2[i]);
  }

  // sort the array
  //
  qsort(array2, N, sizeof(char), compare_chars);

  // print out the sorted values
  //
  fprintf(stdout, "After:\n");
  for (long i = 0; i < N; i++) {
    fprintf(stdout, "array[%d] = %c (%d)\n", i, array2[i], array2[i]);
  }
  
  // exit gracefully
  //
  return 0;
}

// a function to compare two doubles
//
int compare_doubles(const void *a, const void *b) {

  // cast the void pointers to doubles
  //
  const double *da = (const double *) a;
  const double *db = (const double *) b;

  // compare the values as doubles
  //
  if (*da < *db) {return -1;}
  else if (*da == *db) {return 0;}
  else {return 1;}

  //  return (*da < *db) - (*da > *db);
}

// a function to compare two chars
//
int compare_chars (const void *a, const void *b) {

  // cast the void pointers to doubles
  //
  const char *da = (const char *) a;
  const char *db = (const char *) b;
  char tmp_a = tolower(*da);
  char tmp_b = tolower(*db);

  // compare the values as chars
  //
  if (tmp_a < tmp_b) {return -1;}
  else if (tmp_a == tmp_b) {return 0;}
  else {return 1;}

  //  return (*da > *db) - (*da < *db);
}

/*
//===========
#include <stdio.h>
// A normal function with an int parameter
// and void return type
void fun(int a)
{
  printf("Value of a is %d\n", a);
}

int main()
{
  // fun_ptr is a pointer to function fun()
  void (*fun_ptr)(int) = &fun;

  // The above line is equivalent of following two
            void (*fun_ptr)(int);
	           fun_ptr = &fun;
  

  // Invoking fun() using fun_ptr
  (*fun_ptr)(10);

  return 0;
}
*/