CPS 109 Computer Science 1: Class Notes 1

Ryerson University
School of Computer Science
CPS109 Computer Science 1

Understand the problem
Develop the algorithm
Work with the code (on paper, in an editor, or using the tools in an IDE)
Compile the code (use the javac command or the option in your IDE to compile)
Understand the compilation errors and go back to step 3 (you are dealing with "syntax")
Run the compiled code (use the java command or the option in your IDE to run the program)
Determine if the program has done what you wanted it to do (here is where "semantic" issues occur)
If the program did not do what you wanted it to do you may have to go back to step 1.

Java is a "write once and run many places" language
The java Language is compliled into Java byte code from a file with a .java extension
the file produced after a successful compilation will have a .class extension
The java byte code lives in the .class file and is interpreted by the Java Virtual Machine (JVM)

Exercises P1.1, P1.2, P1.3, P1.5, P1.6, P1.7, P1.8, P1,9

The first computers were actually women who held the military job classification of "computer" which is what they did--they worked in teams to perform simple mathematical operations and pass the answers on to others who would combine those answers with others to come up with a final answer to a much larger problem.
Electronic Numerical Integrator And Computer (ENIAC). It spanned 150 feet in width with twenty banks of flashing lights indicating the results of its computations. ENIAC could add 5,000 numbers or do fourteen 10-digit multiplications in a second.
"ENIAC" on a 7.44 by 5.29 sq. mm chip using a 0.5 micrometer CMOS technology. Even this technology is old now but I refuse to keep changing these graphics ;-) (Moore School of Electrical Engineering)
The first manned lunar-landing occurred on July 20, 1969 when Apollo 11descended to the moon's surface.

"The Eagle" had to be landed manually by astronauts Neal Armstrong and Buzz Aldrin, as their onboard "Apollo Guidance Computer" couldn't process instructions fast enough as the landing module sped toward a field of boulders.
When I was a teen around 1977, one of the first personal computers I ever used was called a Challenger 4P, it came in a kit in parts and you had to supply your own TV and tape recorder. It had 4K of memory and was very slow and it had a demo game called "Lunar Lander". The game simulated the lunar landing mission of Apollo 11. The game would often crash the computer. The computer cost about $2000.
This is a Lunar Lander Applet written in Java that will run in most browsers on most machines. It cost nothing but I bet it will still occasionally crash Windows machines.