Questions

1. What is a pure function?
2. How is immutability related to pure functions?
3. How can you tell the compiler to prevent changes to a variable that's passed by value?
4. How can you tell the compiler to prevent changes to a variable that's passed by reference?
5. How can you tell the compiler to prevent changes to a pointer address that's passed by reference?
6. How can you tell the compiler to prevent changes to the value that's pointed by a pointer?