A pure function is a type of function that has two main properties: it always produces the same output for the same input and it has no side effects. This means that when you call a pure function with specific arguments, you can expect a consistent result each time, regardless of when or how many times it is called.In the context of smart contracts and blockchain, pure functions are important because they enhance predictability and reliability. Since they do not change the state of the blockchain or interact with external data, they can be executed without the risk of unintended consequences.By relying on pure functions, developers can create more secure and efficient smart contracts. Since the outcomes depend solely on the inputs, they are easier to test, verify, and reason about. This reduces the likelihood of errors or exploits, contributing to the overall integrity of decentralized applications.