1. CSCI 171 Presentation 1

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

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

4. History of C Bell Telephone Laboratories (1972) Dennis Ritchie (also created UNIX) A - B - C

5. Initially Many Versions Incompatibility ANSI –American National Standards Institute ANSI Standard C

6. Advantages of C Powerful, Flexible –Operating Systems –Applications software –Compilers Popular Portable Modular (should be written in functions)

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

8. Necessary Information Is computer program required? Inputs/Outputs Formulas Organization (flow of logic)

9. Ex: Find area of a circle Is computer required? Inputs / Outputs –Need the radius of circle as input –Area will be the output Formulas –Area = pi * radius ^ 2

10. Find area of circle - continued Flow of logic: –Request radius of circle –Calculate area = pi * radius ^ 2 –Output area

11. Steps in C programming cycle Use editor to create source code Compile source code into object code Link object file into executable file Execute file

12. Use editor to create source code Any editor can be used –Editor supplied with language Any text based editor DOS editor Notepad Write program following syntax of language Save file as: filename.c

13. Compile Source Code Different compilers use different commands Most (such as Borland, Code Warrior) have IDE - can compile via GUI interface Process creates a new file: filename.obj This file is object code - in format readable by machine

14. Link object file Most compilers will do this via GUI interface as well (may combine compiling and linking) Links internal C library functions (such as printf, scanf) with source code Creates new file: filename.exe

15. Execute Program Program can now be executed –Type filename at DOS prompt –Most compilers allow program to be run via GUI interface may combine compiling, linking, and running Finished product can be shared –source code does not have to be shared

16. Using the CodeWarrior compiler Open up CodeWarrior through the Start Menu –Metrowerks CodeWarrior…CodeWarrior IDE Select New… from the File menu Select 'Win32 C Stationary‘ Enter (or select) the location Enter the project name Click 'Ok‘ Click on the + next to 'Win32 Console App‘ Double click 'C Console App‘ Open up the 'Source' folder by clicking on the + next to it Double click main.c - this will open up a text based editor where you can type your program (there will be some code in there automatically, you can delete it or change it) Write the source code Run the program by selecting Run from the Project menu.

17. Sample C Program – Circle Area #include int main( void ) { const double pi = 3.14159; double radius = 0.0, area = 0.0; printf("Enter the radius of the circle: "); scanf("%lf", &radius); area = radius*radius*pi; printf("The area of the circle is: %lf", area); }