Use of 'const' for function parameters

Question

How far do you go with const? Do you just make functions const when necessary or do you go the whole hog and use it everywhere? For example, imag

Answer 1

const is pointless when the argument is passed by value since you will not be modifying the caller's object.

const should be preferred when passing by reference, unless the purpose of the function is to modify the passed value.

Finally, a function which does not modify current object (this) can, and probably should be declared const. An example is below:

int SomeClass::GetValue() const {return m_internalValue;}

This is a promise to not modify the object to which this call is applied. In other words, you can call:

const SomeClass* pSomeClass;
pSomeClass->GetValue();

If the function was not const, this would result in a compiler warning.