Pozamieniaj "," na spacje w pliku wejściowym i śmiało:
FILE *inp;FILE *out;char path_in[] = {"in.txt\0"};char path_out[] = {"out.txt\0"};int x, y, z;inp = fopen(path_in, "r");out = fopen(path_out, "w");//w pętli fscanf(inp, "%d %d %d", &x, &y, &z);fprintf(out, "%d %d %d", x, y, z);