What is the difference between const and mutable in C++?

What is the difference between const and mutable in C++?

In C++, 'const' indicates that a variable's value cannot be changed after initialization, while 'mutable' allows a member of a const object to be modified.

Can you give me an example of using mutable?

Sure! If you have a class with a 'mutable' member, you can modify that member even in a const member function.

Why would I use mutable instead of just making the whole object mutable?

Using 'mutable' allows you to maintain the constness of the object while still allowing specific members to change, which can be useful for caching or lazy initialization.

Are there any performance implications of using mutable?

Generally, using 'mutable' has minimal performance impact, but it can lead to more complex code if overused, so it should be used judiciously.