-+ if (f == NULL)
-+ printf("cannot open such file\n");
-+
-+ while (fgets(line_input, 128, f) != NULL){
-+ if (!strcmp(strtok(line_input, " "),"sdnc_ip:")){
-+ char * ip = strtok(NULL, " ");
-+ char * num = strtok(ip, ".");
-+ sdnc_addr->data[0] = atoi(num);
-+ for (int i = 1; i < 4; i ++){
-+ num = strtok(NULL, ".");
-+ sdnc_addr->data[i] = atoi(num);
++ if (f != NULL){
++ while (fgets(line_input, 128, f) != NULL){
++ if (!strcmp(strtok(line_input, " "),"sdnc_ip:")){
++ char * ip = strtok(NULL, " ");
++ char * num = strtok(ip, ".");
++ sdnc_addr->data[0] = atoi(num);
++ for (int i = 1; i < 4; i ++){
++ num = strtok(NULL, ".");
++ sdnc_addr->data[i] = atoi(num);
++ }