What are the differences between constexpr and macros in C++11?

What are the differences between constexpr and macros in C++11?

In C++11, constexpr is a keyword that allows you to define functions and variables that can be evaluated at compile time, while macros are preprocessor directives that perform text substitution before compilation. constexpr provides type safety and scope, whereas macros do not.

Can you give me an example of using constexpr?

Sure! Here's a simple example:

constexpr int square(int x) {
    return x * x;
}

int main() {
    constexpr int result = square(5); // result is evaluated at compile time
}

What about macros? How would I define a square macro?

You can define a square macro like this:

#define SQUARE(x) ((x) * (x))

int main() {
    int result = SQUARE(5); // result is evaluated at runtime
}

What are the advantages of using constexpr over macros?

The advantages of using constexpr include type safety, better debugging support, and scope management. Macros can lead to unexpected behavior due to their text substitution nature, while constexpr functions are treated like regular functions.