Introduction to Computer Science

Lecture by lecture outline

1. We presented an example of an applet - Example1Shalom.java, containing a few simple drawing instructions.

2. We presented a simple application - Example2Simple.java. We discussed the following:
   • Basic instructions.
   • The four integer types - byte, short, int and long.
   • The two real types - float and double.
   • Variables and constants.

3. We covered the following:
   • The "for" and "if" statements.
   • Nested loops.
   • Random numbers.

4. We presented an application - Example3GCD.java - dealing with two algorithms for calculating the greatest common divisor of integers. The first algorithm is a naive one, stemming directly from the definition, and the second is the Euclidean algorithm. The algorithms are implemented by static functions residing at a separate class.

5. Additional primitive data types: char and boolean.

6. We covered the following:
   • Strings.
   • Arrays.
   • Conversions.
   • Introduction to recursion.

7. Simple examples of recursion:
   • Example4Pascal.java - calculating binomial coefficients recursively.
   • Example5Tangent.java - computing recursively (approximately) the function tg at any point (employing the formula for the tangent of a double angle, given the tangent of the angle).
   • Example6KochSnowflake.java - an applet with a (finite approximation of a) fractal known as Koch's Snowflake.

8. More examples of recursion:
   • Example7SinCos.java - recursive computation of the functions sin and cos, using formulas for the sine and cosine of a double angle.
   • Example8Subsets.java - enumerating all subsets of size k of {1,2,...,n}.
   • Example9Hanoi.java - the classical Towers of Hanoi Problem.

9. We discussed the semantics of simple programs, and then gave an introduction to objects via a simple example - Example10Customers.java .