1. Key Ideas from day 1 slides
CS Kaminski

2. Program (app) Software Program recipe
Makes computer “smart”
controls HW
hides most HW (& low-level SW) from user
solution to a problem
Program
recipe
detailed step-by-step set of instructions
tells computer exactly what to do
processes data

3. Programming = Problem solving
Understand problem & requirements I P O
Design modular program
Design algorithms
Code solution
Test & debug

4. algorithm written in pseudocode (or flowchart or . . .)
pseudocode implemented in high level language (Java or …) (source code)
source code translated into machine language (all 0’s and 1’s) by a compiler

5. IPO (IPSO)
Input  Processing  Output & Storing

6. IPO (IPSO) HUMAN HW SW see/hear  think & remember  speak/write
mouse/KB …  CPU & RAM & disk  screen, … SW
data  process & store  data
(user/file/DB) (user/file/DB)
^^^^^^^^^^^^^
“the PROGRAM”

7. IPO (IPSO) PROGRAM program’s METHOD
user input  process & store  screen display
mouse clicks   DB
data in a form 
program’s METHOD
input parameters  procedure  return value
[& local variables]
[& class’s instance variables]

8. Modular programming Program = a collection of small modules module:
(in Procedural Programming)
an IPSO procedure (or function)
(in Object Oriented Programming)
a Class (object)
a IPSO method (~ a procedure) in a class
Programming = write modules
Top-down or bottom-up

9. Structured Programming
methods made from STACKING & NESTING:
Sequence
do action1
do action2
...
2) Selection
if conditionX is true then
do action1 ...
else
do action2 ...
3) Repetition
while conditionY is true then
{ do action1 }

10. Procedural Programming (PP)
program = set of procedures
procedure (= method) NAMED set of statements which do a specific task
procedure
data passed IN to it (from caller)
it PROCESSES data
it sends results data OUT (to caller)

11. Object-Oriented Programming (OOP)
focus: create objects (vs. procedures)
Object = both
Data = attributes of object
Procedures = methods behaviors of object
- services users of object might need

12. Programming Determine: = problem-solving   solution
WHAT needs to be done
HOW to do it (algorithm)
= problem-solving   solution
Solve the right problem AND
Solve the problem right

13. Steps in programming Requirements specification [what]
I P O
Program design [how]
I P S O, algorithm, modules, GUI
Coding [Java]
Test & debug
compile errors / logic errors / runtime errors
validate output results
Document
Maintenance

14. A Good Program gives correct output follows client/designer’s specs
functionality
output
runs fast
is compact (space)
clear & easy to change

15. Algorithm (P of IPSO) EXAMPLE: find sum of 1st 100 integers
User view: BLACK box
Programmer view: WHITE (“clear”) box
( actual code)
Which algorithm?
Look up - table / file / DB
Ask - crowdsource micro-task on internet
Calculate – Algor. A … + 100
Calculate – Algor. B (100 * (100+1)) / 2

16. Basic Program Operations
1) Actual Work
arithmetic ( * / %)
comparison ( == < > and, or, not)
2) Move/store data
Assignment (=) memory  memory
I/O (read)
keyboard /mouse/touchscreen/file/…  memory
I/O (write)
memory  screen/printer/file/…

17. 3) Control flow (next instruction to run)
default: next line
maybe do next line(s) (if, switch)
do next line(s) multiple times (loop)
go to line elsewhere & return here (call)
4) Packaging
method headers
class headers

18. Why Java? “cross platform” - portable
program written for 1 type of device/HW/OS runs on ANY OTHER device/HW/OS without rewriting/recompiling program

19. Compiler (traditional)
Compiler = a program (IPO)
translates:
Input data: source code file
Output data: machine language file
also finds syntax errors
spelling, grammar, structure errors
that violate rules of that language .

20. for a specific CPU / OS [simplistically]
write program
in high-level lang. (BASIC, C, C++, COBOL,…)
using text editor or IDE
save it as a source code file
compiler translates source code file into executable code file (SomeProgramName.exe)
for a specific CPU / OS [simplistically]

21. Java compiler compiler translates Java source file (.java)
into file containing byte code instructions (.class)
byte code instructions: the “machine language” of the Java Virtual Machine (JVM) [these can NOT be executed directly by a CPU]

22. JVM program that emulates a hardware CPU
JVM executes each byte code instruction, as it’s read (unlike a compiler that produces .exe file)
Java = an interpreted language

23. Program Development Text editor (or IDE) Source code (.java)
saves Java statements
Java compiler
(javac)
is read by
Byte code (.class)
produces
Java
Virtual Machine
(java)
is interpreted by
Program
Execution
results in

24. Java programs portable
program written for 1 type of computer
runs on wide variety of computers (with little/no modification) (e.g., applets from web)
“compiled” Java .class program portable
specific JVM’s exist for many platforms:
Windows, Mac, Linux, etc.

25. 2 ways to compile Java program
command-prompt (B&W) window
javac is Java compiler (for specific JVM)
to compile: javac SomeProgram.java
IDE automates (& hides) this
icon to build (instead of compile)
automatic build when program is run