hedgezzz的部落格

網路上找到很好用的指標程式如下 :

template<class T>
static inline T** alloc( size_t h, size_t w )
{
    typedef T* ptr_type;
    ptr_type* m;
    m    = new ptr_type[h];
    m[0] = new T[h*w];
    for(size_t i=1;i<h;i++) m[i]=m[i-1]+w;
    return m;
}

template<class T>
static inline T** share( T* data, size_t h, size_t w )
{
  typedef T* ptr_type;
  ptr_type* m;
  m    = new ptr_type[h];
  m[0] = data;
  for(size_t i=1;i<h;i++) m[i]=m[i-1]+w;
  return m;
}

template<class T>
static inline void release( T** ptr, bool is_shared = false )
{
  if(ptr && !is_shared) delete[] ptr[0];
  if(ptr) delete[] ptr;
}

int main()
{
    float** tab;
    int width  = 5;
    int height = 3;
    tab = alloc<float>(height, width); // column first

    for(int r = 0;r<height;++r)
    {
         for(int c = 0;c<width;++c)
        {
            //tab[r][c] = 1./(1+r+c);
            tab[r][c] = (r+c) / 2.0 ;
        }
    }

    release(tab);

}