Allegro 4 text output

Question

I'm trying to display the text contained in a text file using Allegro 4, I have no trouble doing it while on the console on C++, but when I try to switch from cout<< to textprintf I get some errors, here's the code of the part I have trouble with:

do{
    char c;
    c=archivo.get();
    textprintf(screen,font,300,300,15,"%s,%d",c,1);
}while(!archivo.eof());     
system("pause");
archivo.close();