Gnuplot label points

void plotStudyIteration(FILE *gPipe, vector<WTANeuron> &Neurons, point2* studyMass, int studyMassSize) {
    register int i;
    fprintf(gPipe, "unset multiplot\nset multiplot\n");
    fprintf(gPipe, "plot '-' u 1:2:3 w labels\n");
    for(i=0; i<Neurons.size(); ++i) {
        fprintf(gPipe, "%lf %lf %d\n", Neurons[i].w[0], Neurons[i].w[1], Neurons[i].index);
    }
    fprintf(gPipe, "e\n");
    fprintf(gPipe, "plot '-' u 1:2 w points ls 0\n");
    for(i=0; i<studyMassSize; ++i) {
        // if(studyMass[i].outValue == 0) {
        //     fprintf(gPipe, "plot '-' u 1:2 w points ls 1\n");
        // }
        // if(studyMass[i].outValue == 1) {
        //     fprintf(gPipe, "plot '-' u 1:2 w points ls 5\n");
        // }
        // if(studyMass[i].outValue == 2) {
        //     fprintf(gPipe, "plot '-' u 1:2 w points ls 7\n");
        // }
        fprintf(gPipe, "%lf\t%lf\n", studyMass[i].x, studyMass[i].y);

        // fprintf(gPipe, "e\n");
    }
    fprintf(gPipe, "e\n");
    fflush(gPipe);
}