Compilare: user.cpp: In function ‘int main()’: user.cpp:22:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(x>M) ^ user.cpp:27:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2;i<=M;i++) ^ user.cpp:32:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=2;j<=M/i;++j) ^ user.cpp:42:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2;i<=M;++i) ^ user.cpp:47:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1;j<=M/i;j++) ^ user.cpp:56:28: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘long long unsigned int’ [-Wformat=] fprintf(fout,"%d\n",sol); ^ user.cpp:17:24: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d",&n); ^ user.cpp:20:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d",&x); ^