why do we use .F when we assign a float variable?

[Amalinda Gamage]

why do we use .F when we assign a float variable?. cant we do it without putting the .F?

e.g. float t = 10.5F ; what does this F mean?

[Angeljruiz]

Heres a old thread about this
http://www.cplusplus.com/forum/beginner/24483/