hello again...
i exec your program.it's perfect .but a problem remaine for me and i know it's my problem.however i discuss it.i want that each time i press a key to input a number , the output change to form that i want.
an example :

keypress=1
output=1

keypress=2
output=12

keypress=3
output=123

keypress=4
output=1,234

keypress=.
output=1,234.

keypress=2
output=1,234.2

please help me.