Contract (software)

a contract defines what to expect.
so you don’t have to read all the underlying code to know what it will do.
this reduces cognitive load

examples

• a image class always has a load and a save method.
  now a dev can use jpgImage and bmpImage and knows it can use .save() on both.
• a method always returns a certain datatype. e.g. load_image() returns type Image

programming