Chapter 5, Problem 19E

Explanation of Solution

Von Koch snowflake using Recursive method:

• A method calls itself is a recursive method.
• In recursive function base case will stop recursion and return value instead of calling function.
• In each recursive call each side is divided into three sides. Each side has length of one by third of previous one.
• Three new sides are drawn by turn line to left by “60⁰”, turn right by “120⁰” and turn left by “600”.

Refer program in Figure 5.6 of textbook and include the following code in the given program to draw the cross.

Function to draw cross:

//Recursive function to draw side of cross

void drawSideofCross(double sidde, int levell)

{

  //If level is 0

  if (levell == 0)

  {

  //Calculate value of x cordinate

  pt.x = int(cos(angle*PI/180)*sidde) + currPt.x;

  //Calculate value of y cordinate

  pt.y = int(sin(angle*PI/180)*sidde) + currPt.y;

  pen->LineTo(pt);

  //Set x cordinate of of current point

  currPt.x = pt.x;

  //Set y cordinate of of current point

  currPt.y = pt.y;

  }

  //If level is not 0

  else

  {

/*Call recursive function drawSideofCross() with prameters (sidde/3) and (levell-1)*/

drawSideofCross(sidde/3,levell-1);

//Rotate 90 degree to left

left (90);

/*Call recursive function drawSideofCross() with parameters (sidde/3) and (levell-1)*/

  drawSideofCross(sidde/3,levell-1);

  //Rotate 90 degree to right

  right(90);

/*Call recursive function drawSideofCross() with parameters (sidde/3) and (levell-1)*/

drawSideofCross(sidde/3,levell-1);

//Rotate 90 degree to right

right(90);

/*Call recursive function drawSideofCross() with parameters (sidde/3) and (levell-1)*/

  drawSideofCross(sidde/3,levell-1);

  //Rotate 90 degree to left

  left (90);

/*Call recursive function drawSideofCross() with parameters (sidde/3) and (levell-1)*/

  drawSideofCross(sidde/3,levell-1);

}

}

//Function to draw cross

void drawCross()

{

/*Call recursive function drawSideofCross() with parameters (side) and (level)�...