Ada is a structured, statically typed, imperative, wide-spectrum, and object-oriented high-level computer programming language, extended from Pascal and other languages. It has built-in language support for design-by-contract, extremely strong typing, explicit concurrency, offering tasks, synchronous message passing, protected objects, and non-determinism. Ada improves code safety and maintainability by using the compiler to find errors in favor of runtime errors.
Ada was originally designed in the early 1980s under contract to the United States Department of Defense (DoD) to supersede over 450 programming languages used by the DoD at that time. Ada was named after Augusta Ada King, Countess of Lovelace (Ada Lovelace, the only legitimate child of the poet Lord Byron, 1815–1852), who has been credited with being the first computer programmer because of her work with Charles Babbage.
The original version is generally known as Ada 83. The language was revised and enhanced in an upward compatible fashion in the early 1990s. The resulting language, Ada 95, was the first internationally standardized (ISO) Object-Oriented Language. Under the auspices of ISO, a further (minor) revision known as Ada 2005 was completed as an amendment to the standard. The most recent version of the language standard is Ada 2012, which has introduced full support for contract-based programming (including subprogram pre- and postconditions) among other features.