Page 111 - Learn To Program With Scratch

The point to take away from this example is that, regardless of the
complexity of the problem we are trying to solve, we can always build the
solution by gluing together a number of smaller, more manageable pieces.
Using this problem-solving technique, we start with short procedures that
solve very simple problems and then use them to create more sophisticated
procedures.

Summary

In this chapter, we introduced a number of fundamental concepts that
will be used extensively in the remainder of this book. First, we explained
the concept of message broadcasting for intersprite communication and
synchronization. After that, we introduced structured programming and
discussed how to use message broadcasting to implement procedures. We
then demonstrated the build-your-own-block feature of Scratch 2.0 and
explained how to pass arguments to procedures to make the procedures
more flexible. We went over several examples that demonstrated dividing
a large problem into smaller, more manageable pieces and explained how
to use procedures as the basic building blocks for creating large programs.
Last, we examined a bottom-up problem-solving technique, in which we
put together known solutions to smaller pieces of a problem to solve the
big problem.
In the next chapter, you’ll learn about the most important concept in
any programming language: variables. This introduction to variables will be
an essential next step in becoming a proficient programmer.

Problems

1. Write different procedures to draw each letter of your name. Name each
procedure for the letter that it draws. Then write a script that calls these
procedures so you can draw your name on the Stage.
2. Create the program shown below, run it, and explain how it works.

Procedures 89

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