DIGITS — Significant binary digits function ¶DIGITS(X) returns the number of significant binary digits of the internal
model representation of X.  For example, on a system using a 32-bit
floating point representation, a default real number would likely return 24.
Fortran 90 and later
Inquiry function
RESULT = DIGITS(X)
| X | The type may be INTEGERorREAL. | 
The return value is of type INTEGER.
program test_digits
    integer :: i = 12345
    real :: x = 3.143
    real(8) :: y = 2.33
    print *, digits(i)
    print *, digits(x)
    print *, digits(y)
end program test_digits