Problems reading and drawing PLY files

Hello everyone,

I am doing my third exercise about ply files. I have to generate a code what it can print PLY files (I have that files).

I have a class with everything what I need (open, create and read PLY files). For example, I can read a PLY file and my read function does a vector with all the points and another one with the face index. It is the code:

int _file_ply::
read(vector<float> &Vertices,vector<int> &Faces)
{
int Next_token,i,j;
int Num_vertices,Num_faces;

if (File!=NULL)
	{
	Next_token=next_token();
	if (Next_token==PLY)
		{
		Next_token=next_token();
		if (Next_token==FORMAT)
			{
			Next_token=next_token();
			if (Next_token==ASCII)
				{
				Next_token=next_token();
				if (Next_token==NUMBER)
					{// head
					Next_token=next_token();
					while (Next_token!=END_HEADER)
						{
						if (Next_token==ELEMENT)
							{
							Next_token=next_token();
							switch (Next_token)
								{
								case VERTEX:
									Next_token=next_token();
									if (Next_token==NUMBER)
										{
          					Num_vertices=(int) Yylval.Real;
										Vertices.resize(Num_vertices*3);
										}
									else error("no number of vertex");
									break;
								case FACE:
									Next_token=next_token();
									if (Next_token==NUMBER)
										{
          					Num_faces=(int) Yylval.Real;
										Faces.resize(Num_faces*3);
										}
									else error("no number of faces");
									break;
								default:
									error("element type not supported");
									break;
								}
							}
						Next_token=next_token();
						}
					// data
					// vertices data
					for (i=0;i<Num_vertices;i++)
						{// vertices data
						for (j=0;j<3;j++)
							{
							Next_token=next_token();
							if (Next_token==NUMBER)
								{
								Vertices[i*3+j]=Yylval.Real;
								}
							else error("no number for coordinate");
							}
						}
					// faces data
					for (i=0;i<Num_faces;i++)
						{
						Next_token=next_token();
						if (Next_token==NUMBER)
							{
							if ((int)Yylval.Real!=3) {
								printf("Face=%d Token=%s
",i,Yylval.Text.c_str());
								error("only triangles supported");;
								}
							}
						else error("no number of vertex indices");
						for (j=0;j<3;j++)
							{
							Next_token=next_token();
							if (Next_token==NUMBER)
								{
								Faces[i*3+j]=(int)Yylval.Real;
								}
							else error("no number for coordinate");
							}
						}
					printf("File readed
");
					}
				else error("no format number");
				}
			else error("no ascii format");
			}
		else error("no format word");
		}
	else error("this is not a ply file");
	return(0);
	}
else
	{
	error("there is not a ply file open");
	return(-1);
	}
}

Well, I need to generate C code to print that points drawing triangles… OK, I have no idea, maybe I need a tip from you because I do not understand that function and what it does correctly…

It is my first time working with C/C++

Well, Im spanish! Sorry for my language!