Editing Design by contract (section)

==Performance implications==
Contract conditions should never be violated during execution of a bug-free program. Contracts are therefore typically only checked in debug mode during software development. Later at release, the contract checks are disabled to maximize performance.

In many programming languages, contracts are implemented with [[Assertion (software development)|assert]]. Asserts are by default compiled away in release mode in C/C++, and similarly deactivated in C#<ref>{{cite web|url=https://msdn.microsoft.com/en-us/library/ttcc4x86.aspx|title=Assertions in Managed Code|website=Microsoft Developer Network |date=15 November 2016 |url-status=live |archive-url= https://web.archive.org/web/20180822105637/https://msdn.microsoft.com/en-us/library/ttcc4x86.aspx |archive-date= Aug 22, 2018 }}</ref> and Java.

Launching the Python interpreter with "-O" (for "optimize") as an argument will likewise cause the Python code generator to not emit any bytecode for asserts.<ref>[https://docs.python.org/3/reference/simple_stmts.html#grammar-token-assert-stmt Official Python Docs, ''assert statement'']</ref>

This effectively eliminates the run-time costs of asserts in production code—irrespective of the number and computational expense of asserts used in development—as no such instructions will be included in production by the compiler.