//=========================================================================
#define PROGRAMMER "SOLUTIONS, NoFrills"
#define PROG_CODE  "soln"
#define COURSE     "ECE-1021"
#define YEAR       (2003)
#define TERM       "Fall"
#define SECTION    (0)
#define ASSIGNMENT "HW #2C"
#define REVISION   (0)
#define TITLE      "Rounding a Floating Point Value"
#define SUBTITLE   "Extra Credit"
#define EMAIL      "wbahn@eas.uccs.edu"
#define FILENAME   "02c0soln.c"
//=========================================================================
// PROBLEM:
//
// For a variable of type double (in Turbo C/C++ v4.5), round a value to
// the number of decimal places requested by the user. The end result
// should be reasonable for any possible value of the variable.
//
// PSEUDOCODE: (Developed in 02c0soln.c)
//
// 1) SET: f = floating point value to be rounded
// 2) SET: n = number of decimal places
// 3) SET: multiplier = 10^n
// 4) IF: (f < 0)
// 4.1) SET: multiplier = - multiplier
// 5) SET: f = f * multiplier
// 6) IF(f < 1e18)
// 6.1) SET: digit1 = (long int) (f/1e9)
// 6.2) SET: f = f - (digit1*1e9)
// 6.3) SET: f = (long int) (f + 0.5)
// 6.4) SET: f = f + (digit1*1e9)
// 7) SET: f = f / multiplier

//== INCLUDE FILES ========================================================
#include <stdio.h> // printf()
#include <math.h>  // pow()

//== FUNCTION PROTOTYPES ==================================================
void PrintHeader(void);

//== MAIN FUNCTION ========================================================
int main(void)
{
	double f;
	int n;
	double multiplier;
	long int digit1;

	PrintHeader();
	printf("\n"); // Print a blank line

	printf("Enter a floating point value: ");
	scanf("%lf", &f);

	printf("Enter the number of decimal places: ");
	scanf("%i", &n);

	multiplier = pow(10, n);

	if(f < 0.0)
		multiplier *= -1.0;

	f *= multiplier;

	if(f < 1e18)
	{
		digit1 = (long int) (f/1e9);
		f -= digit1*1e9;
		f = (long int) (f + 0.5);
		f += digit1*1e9;
	}
	f /= multiplier;

	printf("The rounded number is: %20.20g\n", f);

	return(0);
}

//== SUPPORT FUNCTIONS ====================================================
void PrintHeader(void)
{
	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);
	printf("========================================"
			 "=======================================\n");

	return;
}