Attempting My String Class

Ok I have the suggestion that Zaei and Cornedbee gave me to use an inherted template, and I have added one of my functions to it to test it out. This is what I have so far:

Code:

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template<typename C, typename T = std::char_traits<C>, typename A = std::allocator<C> >
class TECHSTRING_CL : public std::basic_string<C, T, A>
{
public:
        bool IsNumeric()
        {
                /*>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>*/
                const string        _DIGITS_C        = "1234567890.";                //Const String To Hold The Values Wanted
                int                                _iRet                = 0;                                        //Temp Return VAR
                /*<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<*/
               
                if(this->length() <= 0)                                                        //If A Bad Or Empty String Is Passed
                        return false;                                                                        //Return False

                _iRet = this->find_first_not_of(_DIGITS_C);                //Make Sure Everything Is There
               
                return (_iRet == -1);                                                                //If The String Is Numeric _iRet = -1
        };
};

typedef TECHSTRING_CL<char> TechString;
TechString s;

---

But when I do the following:
s = "123456";

I get:
error C2679: binary '=' : no operator found which takes a right-hand operand of type 'const char [7]' (or there is no acceptable conversion)

So whats up?

There are a few things that aren't properly inherited. Those are the constructors and the assignment operators (including combined assignment like +=), you have to rewrite these (by calling the parent of course).

Hmm, I have been trying to figure this out with no luck. Can you give me an example.

Here is an example:

Code:

---

class A
{
public:
        A();
        A(int);
        A& operator = (int);
        A& operator += (int);
};

class B : public A
{
};

int main()
{
        B b1(1); // error, constructor not inherited
        B b2;
        b2 = 1;  // error, operator = not inherited
        b2 += 1; // ok,    operator += IS inherited
        return 0;
}

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The solution to your problem would be to add constructors and assignment operators to your derived class, that just call the parents constructors / assignment operator:

Code:

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typedef std::basic_string<C, T, A> string_type;
inline TECHSTRING_CL& operator = (const char* str)
{
        string_type::operator = (str);
        return *this;
}

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