1. Instructor: Chien-Ho Ko
Introduction to C
Instructor: Chien-Ho Ko

2. Outlines Introduction to Computers Programming Language
C Programming Environment
How to Run C Programs
First Program

3. Introduction to Computers
Computer VS Computer Systems
Computer Hardware
Categories of Software

4. Computer VS Computer Systems

5. Computer VS Computer Systems
Hardware
(the computer)
Data
(information)
Software
(program)
People
(User)

6. Computer Hardware

7. Computer Hardware
Memory
Storage
Processor
Output
Input
Output

8. Categories of Software
System software: tells computers how to use its own components: Windows, Unix, Linux, Macintosh… (interpreter between Hardware & application)
Application software: tells computers how to accomplish specific tasks

9. Programming Language What is Programming Language Machine Languages
Assembly Languages
High Level Languages

10. What is Programming Language
A set of instructions that perform a specific task
What is Programming Language
An artificial & formal language making up instructions and a set of precise grammar rules

11. Machine Languages The natural language of a computer Drawbacks
Instructions are extremely difficult
Simple problems require large number instructions
Machine-dependent
Un-portable

12. Assembly Languages
Instructions consists of English-like abbreviations to make computers easier to program.
Drawbacks
Simple problems require large number instructions
Machine-dependent
Un-portable
L 1, GROSSPAY
S 1, TAX
ST 1, NETPAY

13. High Level Languages Instructions are quite English-like
Single instruction: operations
Drawback
Must be converted to machine languages
High level
Assembly
Machine
NETPAY = GROSSPAY - TAX;

14. C Programming Environment
Why C
How Does C Work
How Does NXC Work
IDE
Language & Libraries

15. Why C-Never Out of Date 1970’s Dennis Ritchie, Bell Lab.
High level (convenient) + assembly (powerful)
Approved by American National Standard Institute
Portable
C++=C + OO + New Feature

16. Why C-Never Out of Date NXC adopts C grammar
The most popular language for NXT

17. How Does C Work
After loader transfers load module to main memory, CPU executes
Process
Text (source program) 
Preprocessor (special instructions) 
Translator (compiler) 
Object Program (machine language) 
Linker (library) 
Load module (Executable machine language)

18. How Does NXC Work
After firmware loads bytecode to memory, CPU executes
Process
Text (NXT code, source program) 
Preprocessor (special instructions) 
Translator (compiler) 
Linker (library) 
Object Program (Next bytecode in PC) 
Object Program (Next bytecode in NXT)

19. Integrated Develop Environment
Text editor+ Preprocessor +C Compiler+ Library + Debug
Microsoft VC++
Borland Turbo C++
Text editor+ Preprocessor +NXC Compiler+ Library + Debug
BricxCC

20. Language & Libraries Language Libraries Provides basic operations
Extend C
Standard libraries: # include <stdio.h>
Programmer-defined libraries: # include <chko.h>

21. How to Run C Programs Edit: Create text, 03_c01.c
Preprocess: Special instructions
Compile: machine language
Link: libraries
Run: executable machine language

22. First Program
1 /*************************************************************
2 Program Filename: 03_c01.c
3 Author: Chien-Ho Ko
4 Purpose: Draw triangle and trapezoid.
5 Output to: Screen
6 *************************************************************/
7 #include <stdio.h> 8
9 int main(void) { 10
11 /* Function body: */ 12
printf(" \n");
14 printf("| |\n");
15 printf("| |\n");
16 printf("| |\n");
17 printf(" \n"); 18
printf(" /\\\n");
20 printf(" / \\\n");
21 printf(" / \\\n");
22 printf(" / \\\n");
23 printf(" \n"); 24
25 return 0;
} /* end function main */

23. First Program
NXC
1 /*************************************************************
2 Program Filename: 03_NXC01.nxc
3 Author: Chien-Ho Ko
4 Purpose: Basic robot control.
5 Output to: Motors
6 *************************************************************/ 7
8 task main()
9 {
10 OnFwd(OUT_A, 75);
11 OnFwd(OUT_C, 75);
12 Wait(100);
13 Off(OUT_AC);
14 } /* end function main */