Should I gcc include what command to to calculate abs??

[boeysue]

gcc abs include

in my server,I use the abs function and include the stdlib.h.
but it doesn't work in the right way.
Should I make compile with what command to include the stdlib.h???
Thanks...

 

[ghbolivar]

calculater abs

include the math.h (use fabs())

compile: (example.c is source code)
gcc example.c -o example.out -lm

enjoy