Console.Writeline doesn't show up

Question

Hi,
I use ConsoleWriteline in my console appl but it shows up only very short in a less than a second and disappears
Can anybody help me what to do please?
Thanks

p.s
example

 if (i == 15 && r == 16)
                            {
                                double Cr = 2048 / counterTotal1;
                                double Nb = counterTotal1 / 256;
                                Console.WriteLine("Cr"+Cr.ToString());
                                Console.WriteLine("Nb" + Nb.ToString());
                            }