What if the code could verify itself?

Design by Contract?A methodology where code explicitly declares what it requires (preconditions) and guarantees (postconditions) embeds verification into every feature. The compiler becomes your QA department.

Preconditions?Conditions that must be true before a feature executes. Guard against invalid inputs. guard inputs. Postconditions?Conditions guaranteed to be true after a feature executes. The function's promises to its caller. verify outputs. Invariants?Conditions that must always be true for an object, checked after every public operation. maintain state. Every contract violation?When code breaks a precondition, postcondition, or invariant—immediately caught at runtime. is caught immediately—not in production.