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

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

In C++, 'const' indicates that a variable's value cannot be changed after initialization, while 'volatile' tells the compiler that a variable may be changed by external factors, preventing optimization.

Can you give me an example of when to use volatile?

Sure! You would use 'volatile' for variables that can be modified by an interrupt service routine or by another thread, ensuring the compiler doesn't optimize them away.

What happens if I use const with a pointer?

Using 'const' with a pointer means that the pointer itself can change to point to different addresses, but the value at the address it points to cannot be modified.

Are there any performance implications of using volatile?

Yes, using 'volatile' can lead to performance overhead because it prevents certain optimizations, making access to the variable slower.

Can you summarize when to use const and volatile?

Use 'const' when you want to protect a variable from being modified, and 'volatile' when a variable's value can change unexpectedly, like in multi-threaded environments.