MCS-170 The Nature of Computer Science

Alice Lecture 1

1. Introduction to Programming in Alice

Overview

Traditional Problem Solving in CS
Problem Solving in Alice
Programming

Traditional Problem Solving in CS

Understand fully the problem or task specification

Sort a list of numbers into nondecreasing order

Design an algorithm to find the solution

Bubble Sort

Implement this algorithm in code

Write the steps in a language like Javascript

Test the code

Load a webpage with this Javascript code and test

Revise the code, if needed

Plusses: Good strategy for solving problems of all types
Minuses: Code implementation is almost always textual,
punctuation and syntax can be a real nuisance

Problem Solving in Alice

Tasks are specific: develop scenarios (stories) about characters

Solution is a storyboard: a sequence of instructions for how characters interact

Implementation of storyboard is done through visual programming,
by dragging commands and objects around on the screen - No Typing!

We test our solution by playing the scene, like we would play a movie.

Programming

Distinguish between algorithms and programs

Algorithm: General description of a series of steps in a solution to a problem or task
Program: Specific sequence of instructions in a language that a computer can understand and carry out

Alice

Algorithm: Storyboard of characters and actions in a scene
Program: Characters (Objects) in the scene and the actions (Methods) they carry out

Why is the study of programming important?

Jobs $$
Understanding how technology works (computers, movies, ipods,etc)
Learning a new way of thinking, of problem-solving
Fun!!

Demo of how Alice works

Start up Alice, explain Class window, Method window, Terrain Screen, adding objects (add a bunny)
Develop simple storyboard for bunny and another character, then implement it with two actions
Review Do in order vs Do tegether constructions
Discuss first homework assignment