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POC++: Using operator of two intrinsic types as a function object
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copied!<p>I have a vector-like class that contains an array of objects of type <code>"T"</code>, and I want to implement 4 arithmetic operators, which will apply the operation on each item:</p> <pre><code>// Constructors and other functions are omitted for brevity. template<class T, unsigned int D> class Vector { public: // Add a value to each item: naive implementation. void operator += (const T&) { for (int i = 0; i < D; ++i) { data[i] += value; } } void operator -= (const T&) { ... } void operator *= (const T&) { ... } void operator /= (const T&) { ... } private: T items[D]; }; </code></pre> <p>Because operators will contain the same boilerplate code (looping over every element and applying appropriate operation), I thought I could generalize it:</p> <pre><code>template<class T, unsigned int D> class Vector { public: void operator += (const T& value) { do_for_each(???, value); } void operator -= (const T& value) { do_for_each(???, value); } void operator *= (const T& value) { do_for_each(???, value); } void operator /= (const T& value) { do_for_each(???, value); } private: void do_for_each(std::binary_function<void, T, T>& op, T value) { std::for_each(data, data + D, std::bind2nd(op, value)); } T data[D]; }; </code></pre> <p>Now, the problem is, how do I pass an operator that takes two intrinsic types and returns <code>void</code> to <code>do_for_each</code>, as depicted in the example above? C++ does not let me do this trick for intrinsic types (<code>"T::operator+="</code> will not work if <code>"T"</code> is <code>"int"</code>).</p>

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