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Unit 1

Getting Started: Preview and Setup

1.1 Welcome

1.2 Mazes, Algorthms & Programs

1.3 Google Account and Portfolio Set Up

1.4 App Inventor Setup

1.5 Blown to Bits

1.6 Joining the Forum

1.7 Successful Learning

1.8 Wrap Up

 

1.2 Mazes, Algorithms & Programs

Let's do some programming

App Inventor is based on a blocks platform named Blockly.

Do the first assignment in the right column. This demo is from Code.org's Hour of Code activity -- maybe you've seen it before? It will help you get a sense of the type of programming you will be doing in this course. It lets you write small Blockly programs (called scripts) to solve Maze puzzles. Can you solve all 20 problems?

Algorithms and Programs

As you learned in that activity, an algorithm is a sequence of precise instructions that solves some problem or performs some computation. A program is an algorithm that is written in a programming language that runs on a computer.


The scripts you created in the Maze demo contain all the essential control structures that programmers use to design algorithms:

Algorithms are Everywhere

Here's an interesting fact: Computer scientists have proven that sequence, selection, and repetition are sufficient to build any algorithm that can be thought of. In other words, any algorithm can be expressed using only sequence, selection, and repetition.

Computer scientists write algorithms to solve problems. And we know now that sequence, selection, and repetition are sufficient to express any algorithm we can think of.

Questions

  1. Are there algorithms we can't think of? Or, to put that another way, are there problems that can't be solved by an algorithm? What do you think?
  2. That's one of the interesting questions we will take up in this course. In a few weeks, you'll know the answer.