An example of using PCL

 #include <pcl/visualization/cloud_viewer.h>  
 #include <iostream>  
 #include <pcl/io/io.h>  
 #include <pcl/io/pcd_io.h>  
 #include <fstream>  
 #include <sstream>  
 #include <string>  
 #include<vector>  
 using namespace std;  
 using namespace pcl;  
 int main()  
 {  
   ifstream myfile("lasercam_000200.txt");  
   vector<vector<double> > pts;  
   string line;  
   int ptNum1=0;  
   while(getline(myfile,line))  
   {  
     istringstream is(line);  
     vector<double> tmp(3);  
     is>>tmp[0]>>tmp[1]>>tmp[2];  
     pts.push_back(tmp);  
     ptNum1++;  
   }  
   myfile.close();  
   ifstream myfile2("raytrace_000200.txt");  
   while(getline(myfile2,line))  
   {  
     istringstream is(line);  
     vector<double> tmp(3);  
     is>>tmp[0]>>tmp[1]>>tmp[2];  
     pts.push_back(tmp);  
   }  
   myfile2.close();  
   cout<<pts.size()<<endl;  
   pcl::PointCloud<pcl::PointXYZRGB> cloud;  
   cloud.is_dense = true;  
   cloud.points.resize (pts.size());  
   for (size_t i = 0; i < cloud.points.size (); ++i)  
   {  
     cloud.points[i].x = pts[i][0];  
     cloud.points[i].y = pts[i][1];  
     cloud.points[i].z = pts[i][2];  
     uint8_t r,g,b;  
     if(i<ptNum1)  
     {  
       r=255;  
       g=0;  
       b=0;  
     }  
     else  
     {  
       r=255;  
       g=255;  
       b=255;  
     }  
     uint32_t rgb = ((uint32_t)r << 16 | (uint32_t)g << 8 | (uint32_t)b);  
     cloud.points[i].rgb=*reinterpret_cast<float*>(&rgb);  
   }  
   pcl::visualization::CloudViewer viewer ("Simple Cloud Viewer");  
   pcl::PointCloud<pcl::PointXYZRGB>::Ptr ptrCloud(&cloud);  
   viewer.showCloud (ptrCloud);  
   while (!viewer.wasStopped ())  
   {  
   }  
   return (0);  
 }