Keypad Programming.

Dear all,

I am using http://www.freetronics.com/pages/16x2-lcd-shield-quickstart-guide#.UwHtgc7pegJ below circuit for reference.
Here i am trying to set latitude here.Date and time can able to Set

Code attached Below in rar file

Modifi.rar (4.87 KB)

Code attached Below in rar file

And the problem is?

I could not able to increnment the float value , SInce my latitude and longitude are in float. I can change only Decimal point> how can make change Floating point Here.