Design by Contract
Design by Contract (DbC) is a software development methodology that formalizes the relationships between software components using precise specifications called contracts. These contracts define preconditions, postconditions, and invariants that must hold true for correct operation, helping to ensure reliability and clarity in code. It originated from the Eiffel programming language but has influenced many modern development practices and tools.
Developers should learn Design by Contract when building robust, maintainable systems where correctness and clear interfaces are critical, such as in safety-critical applications, large-scale enterprise software, or APIs. It helps prevent bugs by explicitly stating assumptions and guarantees, facilitates debugging through contract violations, and improves documentation by making specifications executable. Use cases include formal verification, test-driven development enhancement, and designing reusable libraries with well-defined behavior.