/***************************************************************************** * fixed.cpp Blitz++ array using a custom type * $Id: fixed.cpp,v 1.6 2004/10/07 01:23:26 julianc Exp $ * This example illustrates how simple it is to create Blitz++ arrays * using a custom type. *****************************************************************************/ #include <blitz/array.h> BZ_USING_NAMESPACE(blitz) // A simple fixed point arithmetic class which represents a point // in the interval [0,1]. class FixedPoint { public: typedef unsigned int T_mantissa; FixedPoint() { } explicit FixedPoint(T_mantissa mantissa) { mantissa_ = mantissa; } FixedPoint(double value) { assert((value >= 0.0) && (value <= 1.0)); mantissa_ = T_mantissa(value * huge(T_mantissa())); } FixedPoint operator+(FixedPoint x) { return FixedPoint(mantissa_ + x.mantissa_); } double value() const { return mantissa_ / double(huge(T_mantissa())); } private: T_mantissa mantissa_; }; ostream& operator<<(ostream& os, const FixedPoint& a) { os << a.value(); return os; } int main() { // Now create an array using the FixedPoint class: Array<FixedPoint, 2> A(4,4), B(4,4); A = 0.5, 0.3, 0.8, 0.2, 0.1, 0.3, 0.2, 0.9, 0.0, 1.0, 0.7, 0.4, 0.2, 0.3, 0.8, 0.4; B = A + 0.05; cout << "B = " << B << endl; return 0; } // Program output: // B = 4 x 4 // 0.55 0.35 0.85 0.25 // 0.15 0.35 0.25 0.95 // 0.05 0.05 0.75 0.45 // 0.25 0.35 0.85 0.45 /* * Note: Just because Array<T,N> supports all possible operators doesn't * mean that a user-defined class has to. You only need to define the * operators you actually use on the array. This works because the ISO/ANSI * draft standard forbids instantiation of unused member functions: * * [temp.inst, paragraph 7] * An implementation shall not implicitly instantiate a function, non- * virtual member function, class or member template that does not * require instantiation. It is unspecified whether or not an implemen- * tation implicitly instantiates a virtual member function that does not * require specialization. */