recursion.c

来自「gcc3.2.1源代码」· C语言 代码 · 共 32 行

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const double M_PI=3.14159265358979323846;

template<int N,int I,int J,int K>
inline double SineSeries()
{
  const double x=I*2*M_PI/N;
  const bool go=K+1!=J;
  return 1.0-x*x/(2*K+2)/(2*K+3)*SineSeries<N*go,I*go,J*go,(K+1)*go>();
}

template<>
inline double SineSeries<0,0,0,0>()
{
  return 1.0;
}

template<int N,int I>
inline double Sine()
{
  const double x=(I*2*M_PI/N);
  return x * SineSeries<N,I,10,0>();
}

int main()
{
  double f=Sine<32,5>();
  return 0;
}