What is mutable

[chinmay.sahoo]

When we declare const, the members in the data cannot be changed. If we require to change one of the data then we can declare to be mutable. It specify that the member can be updated even it is member of the constant object.

[TomClarke]

Mutable and immutable are words meaning "can change" and "cannot change" respectively. The meaning of the words is the same in the IT context:
- a mutable string can be changed
- an immutable string cannot be changed.