Russian Qt Forum

QVector <double> x_(10000),y_(10000);
...
float step=0.01;
float xx=x[1];
while (xx<=x[N-1])
{
     x_[k]=xx;
    y_[k++]=Fun(a,b,c,d,xx);
    xx+=step;
}

ui->graf->graph(0)->setData(x_, y_);