Benefits of using “const” with scalar type? (e.g. “const double” or “const int”)

Question

///////////////////////////////////////
class A {
    ...
    const double funA(void)
    {...}
};

A a;
double x = a.funA(); 
// although the intention is to
// enf         


        

Answer 1

When returning by value the constant has no effect as it cannot be enforced anyway. Some compilers issue a warning. However it DOES make sense to return a pointer/reference to constant data.

When passing an argument into a function it is preferable (safer, allows for compiler optimizations) to pass it as a constant unless you absolutely need to change the data.