[*] about gcc

[ÕÅÏþÀÚ@murphy.debian.org, [zhangxiaolei]@murphy.debian.org <maths@21cn.com>]

hello everybody:

i am using debian 2.1r4, i install it use deselect's preselect "scientific 
workstation". i found my gcc doesn't allow me to use "sqrt", for example:

this is a c file: a.c

#include "stdio.h"
#include "math.h"
main(){
printf("%f\n",sqrt(2));
}

and execute "cc a.c"

i get:
/tmp/ccc00242: In function 'main':
/tmp/ccc00242(.text+0xb): undefined reference to 'sqrt'

so i had to use g++ instead, and it worked!

i had use this gcc to campile some math software such as "pari", "simath","rlab"...and 
it work very well, not any error reported.

what is the problem? 


thank you
maths
2000.2