I have a form made it with text boxes, in which I input a number and use this number to sum with other text box and put the result in a label.

I transfer the input in the text boxes to a variable (xbiz and xbder) and I sum plus "5.2"

My problem is when one of the text boxes is empty (in blank) the script give me an error of "ILLEGAL FLOAT VALUE!"

How can solve this problem?

Here is my code:

#FORM
echo "FG 999999" >> $gui_in
echo "FONT cbr18" >> $gui_in
echo "BG 901010" >> $gui_in
echo "LABEL LOCATINES" >> $gui_in
echo "FG 101090" >> $gui_in
echo "FONT cbr18" >> $gui_in
echo "BG 708787" >> $gui_in

echo "TEXT xbiz X_BOT_IZQ" >> $gui_in
echo "TEXT xbder X_BOT_DER" >> $gui_in

#Calculation
set varx = `echo " 5.2 + $xbiz" | bc -l`
set vary = `echo " 5.2 + $xbder" | bc -l`

#After calculate the values of the two variables (varx and vary) I use the result in the following line:

COM display_layer,name=comp,display=yes,number=1
COM add_pad,attributes=no,**x=${varx},y=${vary}**,symbol=${sizefido},polarity=positive,\
angle=0,mirror=no,nx=1,ny=1,dx=0,dy=0,xscale=1,yscale=1