Compilare: user.cpp: In function ‘void DFS(int, int)’: user.cpp:28:66: warning: operation on ‘sf’ may be undefined [-Wsequence-point] while(sf) fprintf(fout,"%d %d %d\n", q[sf--], x, q[sf--]); ^ user.cpp:35:66: warning: operation on ‘sf’ may be undefined [-Wsequence-point] while(sf) fprintf(fout,"%d %d %d\n", q[sf--], x, q[sf--]); ^ user.cpp: In function ‘int main()’: user.cpp:43:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d %d",&N,&M); ^ user.cpp:46:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d %d",&x,&y); ^