Compilare: main.cpp: In function 'std::vector<std::complex<double> > fft_inv(std::vector<std::complex<double> >&)': main.cpp:97:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<x.size();i++) ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:129:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (sz < max(a.size() , b.size())) ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:156:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<c.size();i++){ ~^~~~~~~~~ main.cpp:108:25: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d",&t); ^ main.cpp:110:29: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d",&n); ^ main.cpp:114:33: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d",&x); ^ main.cpp:117:29: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d",&m); ^ main.cpp:121:33: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d",&x); ^