GDB Howto , 9,14,1999, writen by jsyeh in R503 

1) need to compile by `gcc -g ooxx.c -o ooxx`
2) the can run `gdb ooxx`
3) some useful command in gdb mode:

gdb> help
gdb> list
gdb> breakpoint
gdb> run <command_line_argument>
gdb> step
gdb> continue
gdb> print <variable>
gdb> display <variable>
gdb> quit

4) other advice:

 a) you can use `xxgdb` as x-window interface
 b) you can also use emacs as the interface of programming and debugging
 c) you can write a makefile for easily programming & debugging

5) some advance of gdb (i am so poor, so i just can describe very few ^^;;)
 a) you can use condition breakpoints, it can help debugging & save time
 b) so many powerful tool you can use.

6) What is the major problem?