C

1
C

• Crash course in robot programming
• 20.02.2007
• Sizarta Sarshar

2
Next two hours

• C Programming
• The C reference
• Traps and pitfalls
• Eyebot Programming
• RoBios software
• Eyebot library
• Code samples
• Tigergutt

3
The C Programming Language

• The C reference guide
• web link
• The operator precedence
• web link

4
Traps and Pitfalls
C makes it easy to shoot yourself in the
foot - B. Stroustrup
The C language is like a carving knife
simple, sharp, and extremely useful in skilled
hands. Like any sharp tool, C can injure people
who do not know how to handle it - A. Koenig
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Traps and Pitfalls

• The faults are grouped in
• Lexical
• Syntactic
• Semantic pitfalls
• Portability pitfalls
• Linkage
• Library functions
• The preprocessor

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Lexical and syntactic faults
y x/p / p points at the divisor
/ a-1 a -1 while (cgetc(in) ! EOF)
while ((cgetc(in)) ! EOF) putc(c,out)
putc(c,out) switch (color) case 1
printf ("red") case 2 printf ("yellow")
case 3 printf ("blue") case SUBTRACT
opnd2 -opnd2 / no break / case ADD
. . .
7
Semantic pitfalls
i 0 while (i lt n) // There
is no guarantee that the adress of yi yi
xi // will be evaluated before i is
incremented i 0 while (i lt n) yi
xi i double s double s,
sqrt() s sqrt (2) s sqrt(2.0) printf
("g\n", s) printf ("g\n", s) if (a b
lt 0) if ((int) ((unsigned) a (unsigned)
b) lt 0) complain() complain()
8
Library functions
include ltstdio.hgt main() char c
while ((c getchar()) ! EOF) putchar
(c) include ltstdio.hgt main() int c
char bufBUFSIZ setbuf (stdout, buf)
while ((c getchar()) ! EOF)
putchar (c)
9
Eyebot Programming

• RoBios software
• Download and install
• Compiler
• Use the shell script gcc68 for compiling a C
  program. It is accessed from the RoBios console.
  Compiling only
• gcc68 -c filename.c
• Compiling and generating an output file for
  download to the Eyebot controller
• gcc68 filename.c
• The result is stored in a file named a.out. In
  order to use custom output names you may use the
  following
• gcc68 filename.c -o filename.out
• If the code makes use of the math library, add
  the extension -lm.
• gcc68 filename.c -o filename.out -lm

10
Eyebot Programming

• Send the file from the host (PC) using RoBios
  console transhex
• transhex filename.out
• In order to start up a program automatically at
  startup, call your downloaded program startup.hex
  and save it in a ROM slot.

11
Tigergutt

• Web link

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The End