如果是STL容器,最小值算法返回迭代器,如果是数组,则返回地址。
下面是求的一个DPoint3d数组中距目标点最短距离的点:
struct distanceCriteria : std::binary_function<DPoint3d,DPoint3d,bool> { distanceCriteria(DPoint3d* targetPt):m_targetPt(*targetPt){} bool operator()(const DPoint3d& pt1,const DPoint3d& pt2) { double dis1 = mdlVec_distanceXY((DVec3d*)&pt1,(DVec3d*)&m_targetPt); double dis2 = mdlVec_distanceXY((DVec3d*)&pt2,(DVec3d*)&m_targetPt); return ( dis1 < dis2 ); } private: DPoint3d m_targetPt; }; DPoint3d* getShortest(DPoint3d* pArray,size_t ptNums,DPoint3d* targetPt) { return std::min_element(pArray, pArray + ptNums, distanceCriteria(targetPt)); }
如果采用C++ 11的lambda表达式,则会简单很多,效果如同在函数里定义函数,实际是定义了仿函数。
DPoint3d* getShortest(DPoint3d* pArray, size_t ptNums, DPoint3d* targetPt) { return std::min_element(pArray, pArray + ptNums, [&](const DPoint3d& pt1, const DPoint3d& pt2)->bool { double dis1 = mdlVec_distanceXY((DVec3d*) &pt1,(DVec3d*)targetPt); double dis2 = mdlVec_distanceXY((DVec3d*) &pt2,(DVec3d*)targetPt); return (dis1 < dis2); }); }