// file: lecture_07/example.cc
//

// local include files
//
#include "example.h"

// method: main
//
// main program starts here
//
int main(int argc, char** argv) {

  // grab the command line arguments as two integers
  //
  long i = atoi(argv[1]);
  long j = atoi(argv[2]);
  fprintf(stdout, "program name = %s\n", argv[0]);
  fprintf(stdout, "argv[1] = %d\n", i);
  fprintf(stdout, "argv[2] = %d\n", j);
  fprintf(stdout, "the value of argc is %ld\n", argc);

  // do some math
  //
  long k = i + j;
  fprintf(stdout, "k [%d] = i [%d] + j [%d]\n", k, i, j);

  long l = i - j;
  fprintf(stdout, "l [%d] = i [%d] - j [%d]\n", l, i, j);

  long m = i * j;
  fprintf(stdout, "m [%d] = i [%d] * j [%d]\n", m, i, j);

  long n = i / j;
  fprintf(stdout, "n [%d] = i [%d] / j [%d]\n", n, i, j);

  k = ((i + j) + (j + j)) + j - i - j + i + j + j;
  fprintf(stdout, "new value of k = %d\n", k);

  k = i * j + i;
  fprintf(stdout, "mult/add: new value of k = %d\n", k);

  k = (i * j) + i;
  fprintf(stdout, "mult/add: new value of k = %d\n", k);

  // let's do some floats
  //
  fprintf(stdout, "------------\n");
  float arg3 = atof(argv[3]);
  float arg4 = atof(argv[4]);
  fprintf(stdout, "program name = %s\n", argv[0]);
  fprintf(stdout, "argv[3] = %f\n", arg3);
  fprintf(stdout, "argv[4] = %f\n", arg4);

  // all float calculations
  //
  float sum = arg3 + arg4;
  fprintf(stdout, "sum = %f\n", sum);  

  sum = arg3 / arg4;
  fprintf(stdout, "sum (division) = %f\n", sum);  

  sum = arg3 * arg4;
  fprintf(stdout, "sum (multiplication) = %f\n", sum);  

  sum = arg3 - arg4;
  fprintf(stdout, "sum (subtraction) = %f\n", sum);  

  // mixed calculations: use casting!
  //
  long z = 27;
  double zz = arg3 * (double)i / (double)j;
  fprintf(stdout, "zz [%f] = arg3 [%f] * i [%d] / j [%d]\n", zz, arg3, i, j);

  // exponentiation
  //
  float sum = pow(arg3, arg4);
  fprintf(stdout, "pow(%f, %f) = %f\n", arg3, arg4, sum);

  //---------------------------------------------------------------------------
  // some additional useful operators
  //---------------------------------------------------------------------------

  // modulo operator
  //
  fprintf(stdout, "%d %% %d = %d\n", i, j, i % j);
  fprintf(stdout, "%d %% %d = %d\n", -i, -j, -i % -j);
  fprintf(stdout, "%d %% %d = %d\n", -i, j, -i % j);
  fprintf(stdout, "%d %c %d = %d\n", j, '%', i, j % i);
  fprintf(stdout, "%d %c %d = %d\n", -j, '%', -i, -j % -i);

  // increment and decrement
  //
  long inc_i = i;
  fprintf(stdout, "i before = %d\n", i);
  inc_i = i;
  fprintf(stdout, "inc_i after = %d\n", ++inc_i);
  inc_i = i;
  fprintf(stdout, "inc_i after = %d\n", inc_i++);

  i++;
  inc_i = i;
  fprintf(stdout, "i before = %d\n", i);
  fprintf(stdout, "inc_i after = %d\n", --inc_i);
  inc_i = i;
  fprintf(stdout, "inc_i after = %d\n", inc_i--);

  // equivalents
  //
  long acc = 0;
  for (long alex = 0; alex < 10; alex++) {
    acc += alex;
    //acc = acc + alex;
    fprintf(stdout, "(%d): %d\n", alex, acc);
  }

  for (long alex = 10; alex > 0; alex--) {
    acc -= alex;
    fprintf(stdout, "(%d): %d\n", alex, acc);
  }

  // non-arithmetic types
  //
  char a = 'z';
  char b = a--;
  fprintf(stdout, "a = %c (%d) b = %c (%d)\n", a, a, b, b);

  char c = 'z' / (long)2;
  fprintf(stdout, "c = %c (%d)\n", c, c);

  // grab a value from the command line
  //
  i = atoi(argv[1]);
  long N = atoi(argv[3]);

  for (long i = 0; i < N; i++) {

    fprintf(stdout, "--- being if/else for i = %d\n", i);
    // check the value of i
    //
    if (i < (long)2) {
      fprintf(stdout, "i [%d] is less than 2 (%d)\n", i, N);
    }
    else if (i < (long)4) {
      fprintf(stdout, "it is a great day for a quiz\n");
    }
    else if (i == (long)5) {
      fprintf(stdout, "i is equal to 5\n");      
    }
    else if (i != (long)6) {
      fprintf(stdout, "i (%d) is not 6\n", i);
    }
    else {
      fprintf(stdout, "*** warning *** (%d)\n", i);
    }
    fprintf(stdout, "--- done with if/else\n");
  }

  // demonstrate logical operators
  //
  long M = atoi(argv[4]);

  bool value = false;

  if (value) {
    fprintf(stdout, "hello world\n");
  }



  if (N == M) {
    fprintf(stdout, "N == M\n");
  }
  else if ((N % 2) && (M % 2)) {
    fprintf(stdout, "both N and M fail the modulo operator\n");
  }
  else if ((N % 2) || (M % 2)) {
    fprintf(stdout, "either N or M failed the modulo operator\n");
  }
  else if (((N != M) || (N % 2)) && ((M % 2) && (N > M))) {
    fprintf(stdout, "N and M are not equal\n");
  }

  // some useful code

  // open a file
  //
  bool status = false;
  FILE* fp = fopen(argv[1], "r");
  if (fp == (FILE*)NULL) {
    fprintf(stdout, "%s: my program failed to open file (%s)\n",
	    argv[0], argv[1]);
    exit(0);
  }
  
  // let's read the file line by line
  //
  long i = 0;
  char buf[999];
  while (fgets(buf, 999, fp)) {
    fprintf(stdout, "line %d: %s", i++, buf);
  }

  // close the file
  //
  fclose(fp);
  */

  // exit gracefully
  //
  return(0);
}