Read File problem

Hello, i am trying to read many different files. The filename has to change to different numbers. It loops 25 times.

For example the first run i want it to ifstream myfile3 (npcs/npc1.txt); but the second run i want it to ifstream myfile3 (npcs/npc5.txt);

so lets say...

npcmapdata[1] = 1
npcmapdata[2] = 5
npcmapdata[3] = 35

I tried this, but i get the error message '+' : cannot add two pointers. I have tried converting it to a string but then i get tons of errors. I really need some help on how to accomplish this. thank you very much.

Code:

---

while (npcloop < 25)
{
npcloop++;
string account2 = "npcs/" + "npc" + npcmapdata2[npcloop] + ".txt";


                                  ifstream myfile3 (account2.c_str());
                                  if (myfile3.is_open())
                                  {
                                        while (! myfile3.eof() )
                                        {
                                          getline (myfile3,npc);
                                          etc etc
}

---

I know its very confusing, but basically i want my file reading loop to constantly change filenames to a number that i am holding in npcmapdata2 arrays.


Thank you very much for any help i receive

char buffer[300];
sprintf(buffer, "npcs/npc%d.txt", npcmapdata2[npcloop]);
string account2 = buffer;

or:
sprintf(buffer, "%s%s%d%s", "npcs/", "npc", npcmapdata2[npcloop], ".txt");

Thank you so very much. Also the fast response was great :).

I think it would look a lot nicer (and be safer) if it was done in c++.