A C++ Exception to the Rules

You can't modify a const can you? Well technically no, but there is one place (before a constructor) where you can. If the parameter used to construct an instance of the Example class is 0 then it allocates an 80 char string and frees it in the destructor.

#include <iostream>

class Example
{
private:
    const char * ptr;
    const bool freeable;
public:
Example(const char * optional):
    ptr( optional ? optional : new char [80]),
    freeable( optional ? false : true ) {}
~Example( ) { if (freeable) delete[] ptr; }
void ViewState(char ID) {
    if (freeable)
        std::cout << ID << " is Freeable" << std::endl;
    else
        std::cout << ID << " is not Freeable" << std::endl;
    }
};


int main(int argc, char * argv[])
{
    Example S(0) ;
    Example T("Hello World") ;
    S.ViewState('S') ;
    T.ViewState('T') ;
return 0;
}


So S is freeable, T is not.