//=========================================================================
#define PROGRAMMER "INSTRUCTOR, The"
#define PROG_CODE  "INST"
#define COURSE     "ECE-1021"
#define YEAR       (2004)
#define TERM       "Summer"
#define SECTION    (0)
#define ASSIGNMENT "Example Code for HW#7"
#define REVISION   (0)
#define TITLE      "Data Analysis, Sorting, Searching"
#define SUBTITLE   "Last Modified on 11 JUL 04"
#define EMAIL      "emailname@domain.com"
#define FILENAME   "randgen.c"
//=========================================================================

//=========================================================================
// PROBLEM
//=========================================================================
//
// This program accepts a command line argument consisting of the name of
// the data file that the User wishes to create. If no filename is given,
// the User is prompted for a name.
//
// The User is then asked to indicate how many data points they wish to
// create and what the minimum and maximum values are.
//
// The program then creates random values and writes them to the file
// per the entered constraints.
//
// This program can be used as demo code for the following topics:
//
// 	Processing Command Line Arguments.
// 	Working with ASCII test files.
//		Detecting the end of a data file.
//		Allocating large blocks of memory from the heap.
//
//=========================================================================
// PSEUDOCODE
//=========================================================================
//
//	1) TASK: Get filename from User.
// 1.1) TASK: Detect if filename provided on command line
// 1.2) IF: Filename on command line
// 1.2.1) TASK: Copy from command line to filename variable.
// 1.3) ELSE:
// 1.3.1) TASK: Prompt User and get filename from keyboard.
// 2) TASK: Prompt for and get constraints from User.
// 2.1) TASK: Get Number of data points.
// 2.2) TASK: Get Minimum value.
// 2.3) TASK: Get maximum value.
// 3) TASK: Create data file.
// 3.1) TASK: Open and verify text file for write operations.
// 3.2) TASK: Create sufficient memory to hold data.
// 3.3) TASK: Create data and store in memory.
// 3.4) TASK: Dump contents of memory to file.
// 3.5) TASK: Close file and free allocated memory
// 4) TASK: Read data file back into memory.
// 4.1) TASK: Open and verify text file for read operations.
// 4.2) TASK: Make one pass to count data times and find min/max.
// 4.3) TASK: Create sufficient memory to hold data.
// 4.4) TASK: Read in data and store in memory.
// 4.5) TASK: Close file
// 5) TASK: Compute and display RMS value of data.
// 5.1) TASK: Compute the sum of the squares of the data.
// 5.2) TASK: Compute the root of the mean.
// 5.3) TASK: Display result.
// 5.4) TASK: Free allocated memory.
//
//=========================================================================
// DEVIATIONS FROM SUBMITTED PSEUDOCODE
//=========================================================================
//
//=========================================================================
// WAIVED COMPILER WARNINGS
//=========================================================================
//
// Linker Warning: No module definition file specified: using defaults
// Reason for Waiver: Can't suppress. Does not have adverse impact.
//

//=========================================================================
//=========================================================================
// CODE SECTION
//=========================================================================
//=========================================================================

//== INCLUDE FILES ========================================================
#include <stdio.h>  // printf(), scanf(), fgets()
						  // FILE, fopen(), fclose(), rewind()
						  // fprintf(), fscanf()
#include <string.h> // fgets(), strcpy(), strlen()
#include <stdlib.h> // exit(), malloc(), free()
						  // rand(), randomize(), RAND_MAX
#include <time.h>   // randomize()
#include <math.h>   // sqrt()

//== MACRO DEFINITIONS ====================================================
#define FALSE (0)
#define TRUE (!FALSE)
#define BLANKLINE printf("\n")
#define NUL ('\0')      // Null character for string termination

//== EXIT CODES ===========================================================
#define NORMAL_EXIT       (0)
#define FAIL_BAD_FILENAME (1)
#define FAIL_WRITE_OPEN   (2)
#define FAIL_READ_OPEN    (3)
#define FAIL_NO_DATA      (4)

//== FUNCTION PROTOTYPES (for Primary Functions) ==========================
void PrintHeader(void);
double rand_dbl(double min, double max);

//== MAIN FUNCTION ========================================================
int main(int argc, char *argv[])
{
	char filename[81];
	int i;
	int points;
	double min, max;
	double rms;

	double *data;
	FILE *fp;

	PrintHeader();
	BLANKLINE;

	//	1) TASK: Get filename from User.
	if(argc > 1)
		strcpy(filename, argv[1]);
	else
	{
		printf("File to create (including extension): ");
		fgets(filename, 81, stdin);
		i = strlen(filename);
		if('\n' == filename[i-1])  // CR/LF at end of string.
			filename[i-1] = NUL;
		else                       // Didn't read entire string.
		{
			printf("Error in filename - aborting.\n");
			exit(FAIL_BAD_FILENAME);
		}
	}

	// 2) TASK: Prompt for and get constraints from User.
	printf("Enter number of data points to create: ");
	scanf("%i", &points);
	printf("Enter the minimum data value: ");
	scanf("%lf", &min);
	printf("Enter the maximum data value: ");
	scanf("%lf", &max);

	// 3) TASK: Create data file.
	// 3.1) TASK: Open and verify text file for write operations.
	fp = fopen(filename, "wt");
	if(NULL == fp)
	{
		printf("Error opening <%s> for writing - aborting.\n", filename);
		exit(FAIL_WRITE_OPEN);
	}
	// 3.2) TASK: Create sufficient memory to hold data.
	data = (double *) malloc(points*sizeof(double));
	// 3.3) TASK: Create data and store in memory.
	randomize();
	for(i = 0; i < points; i++)
		data[i] = rand_dbl(min, max);
	// 3.4) TASK: Dump contents of memory to file.
	for(i = 0; i < points; i++)
		fprintf(fp, "%.6f\n", data[i]);
	// 3.5) TASK: Close file and free allocated memory
	fclose(fp);
	free(data);

	// 4) TASK: Read data file back into memory.
	// 4.1) TASK: Open and verify text file for read operations.
	fp = fopen(filename, "rt");
	if(NULL == fp)
	{
		printf("Error opening <%s> for reading - aborting.\n", filename);
		exit(FAIL_READ_OPEN);
	}
	// 4.2) TASK: Make one pass to count data items and find min/max.
	points = 0;
	if(1 == fscanf(fp, "%lf", &rms))
	{
		min = max = rms;
		do
		{
			points++;
			if(rms < min)
				min = rms;
			if(rms > max)
				max = rms;
		} while(1 == fscanf(fp, "%lf", &rms)); // rms used as scratch space
	}
	else
	{
		printf("No data retrieved from file - aborting.\n");
		exit(FAIL_NO_DATA);
	}
	printf("File <%s> contains %i data points.\n", filename, points);
	printf("Minimum = %.6f\n", min);
	printf("Maximum = %.6f\n", max);
	// 4.3) TASK: Create sufficient memory to hold data.
	data = (double *) malloc(points*sizeof(double));
	// 4.4) TASK: Read in data and store in memory.
	rewind(fp);
	for(i = 0; 1 == fscanf(fp, "%lf", &data[i]); i++);
	// 4.5) TASK: Close file
	fclose(fp);

	// 5) TASK: Compute and display RMS value of data.
	// 5.1) TASK: Compute the sum of the squares of the data.
	for(i = 0, rms = 0.0; i < points; i++)
		rms += data[i]*data[i];
	// 5.2) TASK: Compute the root of the mean.
	rms = sqrt(rms /(double) points);
	// 5.3) TASK: Display result.
	printf("The rms value of the data is %f.\n", rms);
	// 5.4) TASK: Free allocated memory.
	free(data);

	return(NORMAL_EXIT);
}

//=========================================================================
// PRIMARY FUNCTIONS (functions called directly by main() )
//=========================================================================

//== FUNCTION PROTOTYPES (for Support Functions) ==========================
int printc(char c, int n);

//== PRIMARY FUNCTIONS ====================================================
void PrintHeader(void)
{
	printc('=', 79); printf("\n");
	printf("Course....... %s-%i (%s %i)\n", COURSE, SECTION, TERM, YEAR);
	printf("Programmer... %s (%s)\n", PROGRAMMER, PROG_CODE);
	printf("Assignment... %s (Rev %i) (Source Code in %s)\n",
		ASSIGNMENT, REVISION, FILENAME);
	printf("Description.. %s\n", TITLE);
	printf("              %s\n", SUBTITLE);
	printc('=', 79); printf("\n");

	return;
}

double rand_dbl(double min, double max)
{
	return( min + (max-min)*( (double) rand() / (double) RAND_MAX ) );
}

//=========================================================================
// SUPPORT FUNCTIONS (functions not called directly by main() )
//=========================================================================

int printc(char c, int n)
{
	while(0 < n--)
		printf("%c", c);

	return(n);
}