It shouldn’t be possible, but users of the rectangle type are setting its length and width fields to negative values. We need to encapsulate these fields and add getter and setter methods to control access to them.
Update the rectangle type so that the program below will compile, run, and produce the output shown.
Move the rectangle type and all its existing methods to a new shapes package.
You’ll need to rename the type and its existing methods so they’re exported from the new package.
Leave the struct fields unexported, however, so they can only be accessed through your getter and setter methods.
The setter methods should return a single error value. If any value less than 0 is passed, return an error value indicating the value is invalid. Otherwise, return nil.
2019/05/31 18:46:50 invalid width: -2.300000
exit status 1