COMPILATION
===========

gccx-stan -g -Wall -I /home/course/cs113/F96/include  -c hw7-koch.c
gccx-stan -g -Wall -I /home/course/cs113/F96/include  -o hw7-koch hw7-koch.o /home/course/cs113/F96/include/turtle.o

EXECUTION TESTS
========= =====


============================================================
hw7-koch /home/course/cs113/GradesF96/HW7/inputs/keystrokes.1

This program will draw Koch's snowflake

Enter the length of one side: Enter degree of snowflake (max = 5): ============================================================
hw7-koch /home/course/cs113/GradesF96/HW7/inputs/keystrokes.2

This program will draw Koch's snowflake

Enter the length of one side: Enter degree of snowflake (max = 5): 
Data files:
==========
==> /home/course/cs113/GradesF96/HW7/inputs/keystrokes.1 <==
4
0

==> /home/course/cs113/GradesF96/HW7/inputs/keystrokes.2 <==
2
2

============================================================



SOURCE FILES
====== =====


/*
 *          File:  hw7-koch.c
 *          =====  ==========
 *         Class:  CAS CS 113
 *    Assignment:  HW7
 *      Due Date:  19 November 1996
 * Last modified:  10 November 1996
 * -----------------------------------------------------
 *
 * USAGE: hw7-koch (no commandline arguments)
 * ======
 *
 * OVERVIEW:
 * =========
 * This program displays a famous fractal known as a Koch Snowflake.  The
 * user is asked to input the length of the sides, and the degree of
 * generation to output for the fractal.
 *
 * Algorithm Notes:  
 * ================
 * A recursive function DrawKochSegment() is used under the wrapper function
 * DrawKochSnowflake() to print each line segment of the fractal.
 *
 * Known Bugs:  none
 * ===========
 *
 * Enhancements:  none
 * =============
 *
 * Error Handling: 
 * ===============
 * User enters a non-numerical number
 *   Error Message: Text displayed as to why input is unacceptable.
 *    Error Action: User is given another chance to re-enter.
 * 
 * Other Comments:
 * ===============
 * Generally, MAX_DEGREE should be kept under 7, as this fractal will
 * take a VERY long time to compute.
 *
 */

/* program shell for hw7, fall 1996 */

/* edit this file, adding CODE and COMMENTS as necessary. */

#include <stdlib.h>
#include "turtle.h"
#include "simpio.h"
#include "genlib.h"

/* --------------------
 * Constant: MAX_DEGREE
 * --------------------
 * Set this to the maximum number of
 * iterations to allow for the fractal
 */
const int MAX_DEGREE = 5;


/* --------------------------------------
 * Function: GetParameters
 * Usage: GetParameters(&length, &degree)
 * --------------------------------------
 * A call to GetParameters() reads in the appropriate input data
 * from the user and places it in "length" and "degree"
 */
void GetParameters(double *lengthPtr, int *degreePtr);


/* ----------------------------------------
 * Function: DrawKochSnowflake
 * Usage: DrawKochSnowflake(length, degree)
 * ----------------------------------------
 * DrawKochSnowflake() draws a fractal Koch snowflake at the
 * current turtle position with segment length of "length" and
 * iteration depth "degree".
 */
void DrawKochSnowflake(double length, int degree);


/* --------------------------------------
 * Function: DrawKochSegment
 * Usage: DrawKochSegment(length, degree)
 * --------------------------------------
 * This function, used by DrawKochSnowflake() recursively
 * draws a segment of a Koch snowflake with length "length" and
 * iteration depth "degree".
 */
void DrawKochSegment(double length, int degree);


int main(void)
{
  double length = 1;
  int degree = 1;

  InitTurtle();

  GetParameters(&length, &degree);

  /* position and orient turtle */

  PlaceTurtle(0.2, length/3.0);
  TurnRight(GetCurrentDirection());	/* sets angle to 0 = directly right */
  TurnLeft(60); 			/* sets angle to 60 degrees */

  DrawKochSnowflake(length,degree);

  return(0);
}

void GetParameters(double *lengthPtr, int *degreePtr)
{
  printf("This program will draw Koch's snowflake\n\n");

  printf("Enter the length of one side: ");
  *lengthPtr = GetReal();
  printf("Enter degree of snowflake (max = %i): ",MAX_DEGREE);
  *degreePtr = GetInteger();
  
 
  if (*degreePtr > MAX_DEGREE) {
    *degreePtr = MAX_DEGREE;
    printf("Your degree is too large. Using %d instead.",*degreePtr);
  }
  if (*degreePtr < 0) {
    *degreePtr = 0;
    printf("Your degree is too small. Using %d instead.",*degreePtr);
  }
}


void DrawKochSnowflake(double length, int degree)
{
  /* Draw a triangle with sides made up of KochSegments */
  DrawKochSegment(length, degree);
  TurnRight(120);
  DrawKochSegment(length, degree);
  TurnRight(120);
  DrawKochSegment(length, degree);
}


void DrawKochSegment(double length, int degree)
{
  /* Base Case -- Draw a straight line */
  if (degree <= 0) {
    DrawTurtle(length);
    return;
  }

  /* Recursive Case -- Draw a Koch segment with a triangle in the
   * middle, which is made up of Koch segments
   */
  DrawKochSegment(length / 3.0, degree - 1);
  TurnLeft(60);
  DrawKochSegment(length / 3.0, degree - 1);
  TurnRight(120);
  DrawKochSegment(length / 3.0, degree - 1);
  TurnLeft(60);
  DrawKochSegment(length / 3.0, degree - 1);
}


/* -----------------------> END OF FILE:  hw7-koch.c <------------------ */