std::accumulate对结构体求和方法

/// test.h
typedef struct stImage
{
	stImage() : width(0), height(0) {}
	stImage(int w, int h) : width(w), height(h) {}
	int width;
	int height;
}stImage;


struct AddImage
{
	stImage operator()(stImage total, const stImage& p) const
	{
		total.width += p.width;
		total.height += p.height;
		return total;
	}
};

/// test.cpp
vector<stImage> vecImg;
stImage sum = std::accumulate(vecImg.begin(), vecImg.end(), stImage(), AddImage());