Point Cloud Registration ICP

I need a piece of code to combine multiple point clouds to one point cloud. Lets say, I have 5 sets of point clouds in 3D and I know the rotations of them according to initial set. Starting from the initial set and adding the other ones by rotating / using ICP algorithm, I want to create full set of point cloud. Just rotating and combining them would be enough because, axis of rotation would not be accurate. Iterative Closest Point (ICP) algorithm or any other if exists needed to match related points. It should be done without using Point Cloud Library (PCL). I will integrate it to Qt project so code needed as Qt C++ project file. Point clouds and rotation will be given and project completion will be done after successful registration of them is done. Thanks