Result is truncate(Number)
   which should be preferred for portability.
This operation works on all numeric types. The result value is the closest integral value that lies between 0 and Number (rounding towards zero).
The result type is the same as the argument type. To convert the type to integer, use integer/2.
In coroutining mode, if Number is uninstantiated, the call to truncate/2 is delayed until this variable is instantiated.
    Result is truncate(1.8).		% gives Result = 1.0
    Result is truncate(-1.8).		% gives Result = -1.0
    Result is truncate(1.0).		% gives Result = 1.0
    Result is truncate(-0.0).		% gives Result = -0.0
    Result is truncate(5).		% gives Result = 5