H_beginner 0 Newbie Poster

I am trying to plot a graph in matlab using c++. But the matlab is only giving me an empty graph.

void portfolio::viewGraph()
{
    double value[20]; //store portfolio value
    double time[20]; //store time
    int i=0,j=1;
    double cash,p;
    ifstream in_file("transactionhistory.txt", ios::in);
    string c;
    while(in_file>>cash>>p>>c>>c>>c>>c>>c)
    {       
        value[i]=(p+cash);
        cout<<p<<endl;


    time[i]=j;
        cout<<time[i]<<endl;
        i++;
        j++;
    }

    Engine *ep;
        if (!(ep = engOpen(NULL))) 
    {
        return ;
    }
    int t=20;
     mxArray *A; // assume a gets initialized, all values
    A=mxCreateDoubleMatrix(1,i, mxREAL);
    memcpy((void *)mxGetPr(A), (void *)value, sizeof(double)*i);
    engPutVariable(ep, "value", A);
    mxArray *B;

// assume a gets initialized, all values
    B=mxCreateDoubleMatrix(1,i, mxREAL);
    memcpy((void *)mxGetPr(B), (void *)time, sizeof(double)*i);
    engPutVariable(ep, "time", B);

    engEvalString(ep, "plot(date,value);" ); 


    engEvalString(ep,"xlabel('Time')");
    engEvalString(ep,"ylabel('Portfolio Value')");

}