gfortran -o result result.f readd.f -I/usr/local/pgplot -L/usr/local/pgplot -L/usr/X11r6/lib  -lcpgplot  -lpgplot -lm -lX11

export PGPLOT_DIR=/usr/local/pgplot
export PGPLOT_DEV=/xw
export LD_LIBRARY_PATH=/usr/local/pgplot