// file: my first program
//
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

// function: myalloc
//
void mymalloc(float** arg, long N) {
  *arg = new float[N];
  fprintf(stdout, "mymalloc: %u\n", *arg);
}

// function: myprint
//
// arguments:
//  FILE* fp: open file pointer
//  float* x: a floating point array
//  long N: the total number of elements
//
// return: a logical value indicating status
//
bool myprint(FILE* fp_a, float* x_a, long N_a) {

  // print
  //
  for (long i = 0; i < N_a; i++) {
    fprintf(stdout, "myprint: (%d) = %f\n", i, x_a[i]);
  }

  // exit gracefully
  //
  return true;
}

// function: mychange
//
// arguments:
//  float* x: a floating point array
//  long N: the total number of elements
//
// return: a logical value indicating status
//
bool mychange(float* x_a, long N_a) {

  // loop over the matrix
  //
  for (long i = 0; i < N_a; i++) {
      *x_a++ = (float)27.0;
  }

  // exit gracefully
  //
  return true;
}

// function: mycopy
//
// arguments:
//  float* x: a floating point array
//  long N: the total number of elements
//
// return: a float* containing the new array
//
float* mycopy(float* x_a, long N_a) {

  // allocate memory
  //
  //  float* rval = malloc(N_a * sizeof(float));
  float* rval = new float[N_a];

  // create a temp pointer
  //
  float* tmp_val = rval;

  // copy the data:
  //  we could use memcpy()
  //
  //  memcpy(rval, x_a, N_a * sizeof(float));
  for (long i = 0; i < N_a; i++) {
    *tmp_val++ = *x_a++;
  }

  // exit gracefully
  //
  return rval;
}

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

  // void pointers
  //
  //  float x[] = {0, 1, 2, 3, 4};
  //  fprintf(stdout, "x[3] = %f (%u %u %f) = %f\n", x[3], x, &x[3], x[3], x[3]);

  /*
  float* ptr = (float*)malloc(5 * sizeof(float));
  for (long i = 0; i < 5; i++) {
    ptr[i] = x[i];
  }
  fprintf(stdout, "ptr[3] = %f\n", ptr[3]);
  */

  // create memory in a function
  //
  float* y = (float*)NULL;
  fprintf(stdout, "main BEFORE: y = %u\n", y);
  mymalloc(&y, 5);
  fprintf(stdout, "main AFTER: %u\n", y);

  // grab the dimensions from the command line
  //
  long Mrows = atoi(argv[1]);
  long Ncols = atoi(argv[2]);
  long Pdepth = atoi(argv[3]);

  // declare an array of floats
  //
  float x[Mrows][Ncols][Pdepth];
  //float x[Mrows][Ncols];

  // set the values
  //
  for (long m = 0; m < Mrows; m++) {
    for (long n = 0; n < Ncols; n++) {
      for (long p = 0; p < Pdepth; p++) {
	x[m][n][p] = (float)(m + n + p);
	fprintf(stdout, "[%d][%d][%d] = %f\n", m, n, p, x[m][n][p]);
      }
    }
  }

  // test how the data is stored in memory
  //
  /*
  long i = 0;
  float* ptr = (float*)x;
  for (long m = 0; m < Mrows; m++) {
    for (long n = 0; n < Ncols; n++) {
      for (long p = 0; p < Pdepth; p++) {
	fprintf(stdout, "%d: x[%d][%d][%d] (mem: %u) = %f\n",
		i, m, n, p, &x[m][n][p], x[m][n][p]);
	i++;
	ptr++;
      }
    }
  }

  fprintf(stdout, "size of x = %u (%u)\n", sizeof(&x), sizeof(ptr));
  fprintf(stdout, "size of chr = %u (%u)\n", sizeof(char*), sizeof(int*));
  fprintf(stdout, "the starting memory location is %u (%p)\n", x, x);
  fprintf(stdout, "x[][][] (%u) = %f (%f)\n", (x+1), *(x+1), *(x+1));
  fprintf(stdout, "x[][][] (%u) = %f (%f)\n", (x+2), *(x+2), *(x+2));
  fprintf(stdout, "x[][][] (%u) = %f (%f)\n", (x+3), *(x+3), *(x+3));
  fprintf(stdout, "x[][][] (%u) = %f (%f)\n", (x+4), *(x+4), *(x+4));
  */

  
  /*
  long i = 0;
  for (long m = 0; m < Mrows; m++) {
    for (long n = 0; n < Ncols; n++) {
	x[m][n] = (float)(i);
	//	fprintf(stdout, "%d: [%d][%d] = %f\n", i, m, n, x[m][n]);
	i++;
      }
    }

  //  fprintf(stdout, "data: \n");
  for (long i = 0; i < Mrows * Ncols * Pdepth; i++) {
    fprintf(stdout, "(%d: %u): %f\n", i, ptr, *ptr);
    ptr++;
  }
//  for (long i = 0; i < Mrows * Ncols; i++) {
//    fprintf(stdout, "(%d: %u): %f\n", i, ptr, *ptr);
//    ptr++;
//  }
*/
  
  // print x
  //
  myprint(stdout, (float*)x, Mrows * Ncols * Pdepth);

  // change x
  //
  mychange((float*)x, Mrows * Ncols * Pdepth);
  fprintf(stdout, "New values:\n");
  myprint(stdout, (float*)x, Mrows * Ncols * Pdepth);
  /*
  /*
  // create a new array
  //
  //float* y = (float*)x;
  float* y = new float[Mrows * Ncols];
  long k = 0;
  for (long i = 0; i < Mrows; i++) {
    for (long j = 0; j < Ncols; j++) {
      y[k++] = x[i][j];
    }
  }
  y[3] = 15.0;

  //float* y = mycopy((float*)x, Mrows * Ncols * Pdepth);
  fprintf(stdout, "X:\n");  
  myprint(stdout, (float*)x, Mrows * Ncols);
v  fprintf(stdout, "Y:\n");  
  myprint(stdout, (float*)y, Mrows * Ncols);
  //  delete [] y;

  long M = 10;
  float* y = new float[M*M];
  memset(y, 0, M*M*sizeof(float));
  y[M*1 + 1] = 27.0; y[M*2 + 2] = 99.0;

  float*z = y;
  long N = 3;
  for (long i = 0; i < N; i++) {
    for (long j = 0; j < N; j++) {
      fprintf(stdout, "y[%d][%d] = (%u) %f <> %u %f\n", i, j, &y[N*i+j],
	      y[N*i+j], z, *z);
      z++;
    }
  }

  short int buf[10];
  FILE* fp = fopen(argv[1], "r");
  fprintf(stdout, "position = %u\n", ftell(fp));
  fread(buf, sizeof(short int), 1, fp);
  fprintf(stdout, "position = %u\n", ftell(fp));
  fclose(fp);

  char* mystr = new char[10];
  char* ptr = (char*)malloc(10 * sizeof(char));
  char* aptr = new char[10];

  aptr[3] = 'a';
  *aptr = 'b';
  aptr[0] = *aptr;
  printf("%c>", aptr[3]);

  void* pstr = (void*)aptr;
  float* joe = (float*)pstr;

  char Joe[] = "JoePicone";
  char* str = Joe;
  fprintf(stdout, "str = %c\n", str[0]);
  str++;
  fprintf(stdout, "str = %c\n", *str);

  double Mary[10]; Mary[0] = 27.0; Mary[1] = 35.0; Mary[2] = -27.0;
  double* psum = (double*)Mary;
  fprintf(stdout, "psum = %f\n", *psum);
  psum++;
  fprintf(stdout, "psum = %f\n", *psum);

  */
  
  // exit gracefully
  //
  return 0;
}