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This is the action that is required whenever either of the touching blocks is true. In other words, whenever the basketball touches either of the beachballs, it must turn to facethe opposite direction and be prepared to move 90 steps in that direction the next time the user clicks the basketball.
A copy of this program has been posted online for your review (see Resources for the URL) . If you don't find the program using that URL, search the Scratch site for the usernamed dbal.
I encourage you to use the information provided above to write this program. Experiment with the code, making changes, and observing the results of yourchanges. Make certain that you can explain why your changes behave as they do.
Just for fun, use blocks from the purple Sound group and add some sound effects to your program.
I also encourage you to write the program described below.
Write a Scratch program named IfWithVar01 that produces the output shown in Image 13 when the user clicks the green flag. (Don't be concerned about matching the values in the x and y variables in Image 13 . )
When the user clicks the green flag, a DrawingPencil sprite draws a pair of orthogonal axes that intersect at the origin in the white Stage area.Make the horizontal axis extend from -200 to 200. Make the vertical axis extend from -100 to 100.
Each time the user clicks the mouse in the white Stage area (after the user has clicked the green flag) , a straight line is drawn from the current location of the DrawingPencil to the location where the mouse click occurred. Image 14 shows an example output after two mouse clicks.
In case you need to sneak a peek at the solution to this programming project, acopy of this program has been posted online for your review (see Resources for the URL) . (If you don't find the program using that URL, search the Scratch website for the usernamed dbal .)
Once you locate the project on the Scratch web site, you can execute it online.
I began by explaining structured programming, the sequence structure, the selection structure, and the loop structure. Then I presented andexplained a Scratch program that illustrates the selection structure. (The sequence structure is so simple that it doesn't require an explanation. The loop structure will be explained in a future module.) The program also illustrates the handling of mouse events and Cartesian coordinates.
Finally, I provided the specifications for a student-programming project for you to write to demonstrate your understanding of what you learned from thefirst program.
Copies of both programs have been posted online for your review (see Resources for the URL) . If you don't find the program using that URL, search the Scratch site for the usernamed dbal .
In the next module, I will teach you about arithmetic operators. In the two modules following that one, I will teach you about relational and logicaloperators and how to use those operators to write the conditional expressions used in selection and loop structures.
This section contains a variety of miscellaneous information.
Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.
I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.
In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freelyavailable on cnx.org and that it was made and published without my prior knowledge.
Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.
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