If a precondition is violated, the effect of the section of code becomes undefined and thus may or may not carry out its intended work. Security problems can arise due to incorrect preconditions.
Often, preconditions are simply included in the documentation of the affected section of code. Preconditions are sometimes tested using assertions within the code itself, and some languages have specific syntactic constructions for doing so.
For example: the factorial is only defined for integers greater than or equal to zero. So a program that calculates the factorial of an input number would have preconditions that the number be an integer and that it be greater than or equal to zero.
Azerbaijan’s PresidentIlham Aliyev, on the first anniversary of his country’s attacks on Artsakh, once again, made threats against Armenia, while Ankara said it will continue to impose precondition on Yerevan to accept Azerbaijan’s sovereignty in return for normalization of relations.