CSCI 115 Computer Programming Overview

Computer Software System Software –Operating systems –Utility programs –Language compilers Application Software

Language Compilers Programming Generations –5 Generations 1GL - Machine Language 2GL - Assembly Language 3GL - Compiled Languages –Procedural »COBOL »C –OOP »Java »C++ 4GL – SQL 5GL

Programming Languages C –Powerful and flexible FORTRAN –Mathematics and engineering COBOL –Business JAVA –Flexible –Web based 100s of others

History of Java –First started in 1990 as Sun’s Green project Digitally controlled consumer devices identified as trend –Oak –Trend did not grow as expected –1994 – WWW popularity –Netscape packaged Java within browser MS Explorer followed suit –Success ultimately depended on e-commerce

Development Tools 1995 – First JDK released by Sun (1.0) –Very limited JDK 1.1 released –Limited GUI creation 1.2 released –Major change – Swing components –Java 2 SDK release 1.2 –Better known as Java 2

Development Tools Many environments within which to create apps –Any text editor –Eclipse –TextPad

Problem Solving Technique Define Problem Devise plan to fix problem Implement the plan Test

Steps in Java programming cycle Use editor to create source code Compile files Link files Execute program

Number Bases Electronic devices –2-state system: On = 1, Off = 0 –Base 2 Converting from non-decimal to decimal base –Expanded form Converting from decimal to non-decimal base –Repeated division of non-decimal base Calculator

Java Program - Base Conversions import java.util.*; public class Bases { public static void main(String args[]) { Scanner s = new Scanner(System.in); int valToConvert = 0, base = 0; System.out.print("Enter the number to convert: "); valToConvert = s.nextInt(); System.out.println(); System.out.print("Enter the base to convert to: "); base = s.nextInt(); System.out.println(); System.out.print(valToConvert + " in base " + base); System.out.println(" is: " + Integer.toString(valToConvert, base)); System.out.println(); }