Explain the Differences Between volatile, mutable, and const Keywords in C++

Differences Between volatile, mutable, and const Keywords in C++

The keywords volatile, mutable, and const play important roles in C++ programming.

volatile tells the compiler not to optimize the variable because its value can change at any time. This is usually used in multithreaded programs. For example:

volatile int flag = 1;

mutable allows a member of a class to be modified, even if the object is declared as const. This is useful when a member variable does not logically affect the constness of the object. Example:

mutable int counter = 0;

const indicates that a variable’s value cannot be changed once assigned. It is used for defining constant values and read-only data. For example:

const int max_value = 100;

Understanding these keywords can improve code performance, readability, and safety.