What is the primary purpose of "input validation" in programming?

The primary purpose of input validation in programming is to ensure the data provided to a program is correct. This process involves checking user inputs to confirm that they meet specific criteria before being processed. Input validation helps prevent errors, maintain data integrity, and protect against malicious inputs that can lead to vulnerabilities, such as injection attacks. By enforcing rules about what constitutes valid input—such as format, range, and type—developers can safeguard their applications from unexpected behaviors and ensure that only appropriate data is accepted, enhancing overall program reliability and security.