CSCI 171

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 <stdio.h> 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); }