c++ istringstream
===

i am trying to write a c++ opengl application to load .OBJ files and i use this code to read
the vertex:

        char buf[256];
    	while(!objFile.eof())
    	{
    		
    		objFile.getline(buf,256);
    		coordinates.push_back(new std::string(buf));
    }
    		

    else if ((*coordinates[i])[0]=='v' && (*coordinates[i])[1]==' ')
    		{
    		float tmpx,tmpy,tmpz;
    		sscanf(coord[i]->c_str(),"v %f %f %f",&tmpx,&tmpy,&tmpz);
    		vertex.push_back(new coordinate(tmpx,tmpy,tmpz));
    		cout << "v " << tmpx << " " << tmpy << " " << tmpz << endl;
    		

    }

so basicly the second pice of code parses the vertex lines from the obj file

    v 1.457272 0.282729 -0.929271

my question is how can i parse this vertex line c++ style using `istringstream`
what would the code below translate to in c++ syntax

    sscanf(coord[i]->c_str(),"v %f %f %f",&tmpx,&tmpy,&tmpz);
        vertex.push_back(new coordinate(tmpx,tmpy,tmpz));
