Compilare: user.cpp: In function ‘void df(int)’: user.cpp:13:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<l[k].size();i++) ^ user.cpp: In function ‘void dft(int)’: user.cpp:27:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<lt[k].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:57:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<r[i].size();j++) ^ user.cpp:38:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&n,&m); ^ user.cpp:41:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&x,&y); ^