B CUSP 110C – Digital Thinking

Exercise 7 + Homework 10: Loops and Conditionals

Goal: To get practice working with loops and conditions.

Recall our owl function from Exercise 6 (Exercise6.Owl.txt):

Notice once again that the owl is a 70 x 100 figure.

Part 0: setup. Modify the given Processing code such that:

1. frameRate is at 30;

2. size is 600x600

3. clear background per each draw().

Now, recall we wrote an owl8() function to draw 8 owls in a row:

Part 1: Make A Flock with for loop. Re-implement the owl8() function by use a for loop. You do not need to worry about changing color or the owl’s claws, just write a for loop to draw the 8 owls in a row.

Part 2: Make a variable number of owls in a row. Make a function with following specification:

Name: drawOwlsInARow(int y, int num)

Parameters:

int y, // the beginning y location of the row of owls

int num // the number of owls to be drawn

Returned type: void

This function draws num number of consecutive owls horizontally starting from x=35, and at the specify y position. For example:

drawOwlsInARow(100, 4); // draws 4 owls in a row beginning at y=100 with first at (35, 100)

drawOwlsInARow(200, 5); // draws 6 5 owls in a row beginning at y=200 with first at (35, 200)

will draw:

Part 3: Hide and seek with owls in a row: recall that mouseX and mouseY tell us the location of your mouse position. Now, use these two variables to test (hint: use if statement) the position of the mouse and draw a row of 8 owls if the mouse Y position is less than 200, or:

if (mouseY< 200)

drawOwlsInARow(200, 8);

Now, draw a row of 6 owls at y=400 if mouseY position is greater than 400.

Part 4: drawOwlsInAColumn: Make a function with following specification:

Name: drawOwlsInAColumn(int x, int num)

Parameters:

int x, // the beginning x location of the column of owls

int num // the number of owls to be drawn

Returned type: void

This function draws num number of consecutive owls vertically starting from y=100, and at the specify y position. For example:

drawOwlsInAColumn(60, 4); // draws 4 owls in a column beginning at x=60 with first at (60, 100)

drawOwlsInAColumn(145, 6); // draws 6 owls in a row beginning at x=145 with first at (145, 100)

will draw:

Part 5: Hide and seek with owls in a column: similar to Part 3, we want to draw columns of owls when:

· Mouse X position is less than 200, draw a column of 4 owls at x=200

· Mouse X position is more than 400, draw a column of 6 owls at x=600 x=400

Now, when you put everything together (and put a red square in the middle), this is what you have: Kelvin’s attempt.

Remember to comment your program!!

Wrap Up: You have practiced working with loops and conditional statements.

· Exercise 7: Post the applet to your Part5 on your personal web-site and send Jack an email.

· Homework 10: e-submit your source code to the class dropbox.

Challenge (5 pt extra credit): Warning, work on extra credit only after you are completely done with the regular assignment. The following program involves very small number of lines of code, but can be rather tricky.

· Remember we can test for if the mouse is within an area by testing for:

o if (mouseX >50 && mouseX<500) ß test for if mouse’s X position is between 50 and 500

· Remember we can find the hundredth digit of a number by integer division of the number by 100, e.g.

o int n = mouseX / 100; //ß n is the hundredth digit of mouseX, e.g., if mouseX is 248, n will be 2, if mouseX is 168, n is 1, etc.

· Now modify your program such that:

o Draw a red rectangle at (50,50) with size 500x500

o When your mouse is inside this area, draw column/row owls with number representing the hundredth mouseX and mouseY digit.

§ the row/column must be drawn at the current mouse position

§ Examples:

· If mouseX=100, mouseY=200, you will draw

o a column of one owl (because mouseX’s hundredth digit is “1”)

o a row of two owls (because mouseY’s hundredth digit is “2”)

· if mouseX=352, mouseY=428, you will draw

o a column of 3 owls (because mouseX’s hundredth digit is “3”)

o a row of 4 owls (because mouseY’s hundredth digit is “4”)

· Here is my solution.