C++ “const” keyword explanation

Question

When reading tutorials and code written in C++, I often stumble over the const keyword.

I see that it is used like the following:

const          


        

Answer 1

The first function example is more-or-less meaningless. More interesting one would be:

void myfunc( const char *x );

This tells the compiler that the contents of *x won't be modified. That is, within myfunc() you can't do something like:

strcpy(x, "foo");

The second example, on a C++ member function, means that the contents of the object won't be changed by the call.

So given:

class {
  int x;
  void myfunc() const;
}

someobj.myfunc() is not allowed to modify anything like:

x = 3;