add below line in your prefix.pch file...this is the simplest way to check screen size, no need to make extra lines of code...
#define IsIphone5 ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )568 ) < DBL_EPSILON )
now whereever you want to check screen size , just make condition like below, and you can do whatever you want....
if(IsIphone5)
{
//your stuff
}
else
{
//your stuff
}
Happy Coding!!!!