A simple example would be instead of this: int temperature_a; int temperature_b; or even: Temperature a; Temperature b; you would have:

A simple example would be instead of this: int temperature_a; int temperature_b; or even: Temperature a; Temperature b; you would have: Celsius a; Fahrenheit b; And an assignment between a and b would be an error, as Celcius and Fahrenheit are different types. Going along this path then, if you can extend the type system enough: Yards width; Yards length; Acre size = width * length; /* this would be okay */ Yards width; Yards length; Yards height; Acre money_bin = width * length * height; /* error */ /* as acre is a measure of area, not volume */ Think of the type of calculations that the Unix command 'units' does, but built into a language instead of an application.