Millised operatsioonid või meetodid erinevad selle poolest, et nende korduv täitmine viib süsteemi oleku muutumiseni, mitte eelneva tulemuse säilitamiseni?

Operations or methods that, when executed repeatedly, change the state of the system rather than simply returning the result, are called side effects.

Examples of such operations:

• Writing or modifying data in a database.
• Sending HTTP requests that change the state on the server.
• Writing to a file or modifying the file system.
• Changing global or static variables.
• Calling functions that change the state of an object or system.

In testing, it is important to distinguish between pure functions (without side effects) and functions with side effects, as the latter require a special approach for verification and isolation.