Weighing machine

Story

In this exercise you'll be modeling a weighing machine.

The weight can be set and retrieved in pounds or kilograms and cannot be negative.

The weight can be displayed in SI units or US units , pounds and ounces.

A tare adjustment can be applied to the weight (for instance to deduct the weight of a container). This can be any value (even negative or a value that makes the display weight negative) as there are doubts about the accuracy of the weighing machine. For security reasons this value cannot be retrieved.

Note that:

display-weight = input-weight - tare-adjustment

Conversion ratios are as follows:

  • 16 ounces to a pound
  • 2.20462 kg to a pound

For Example:

  • 60 kilograms == 132.2772 ponds
  • 132.2772 pounds == 132 pounds 4 ounces

Tasks

These are example tasks that fit the weighing machine exercise:

  • Allow the weight to be set on the weighing machine
  • Ensure that a negative input weight is rejected
  • Allow the US weight to be retrieved
  • Allow the machine's units to be set to pounds
  • Allow a tare adjustment to be applied to the weighing machine

Implementations