Compilare: user.cpp: In function ‘void readandturn()’: user.cpp:61:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,x,y,z; ^ user.cpp: In function ‘int queryandupdate()’: user.cpp:75:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<h[k].size();i++) ^ user.cpp:74:9: warning: unused variable ‘nr’ [-Wunused-variable] int nr=0; ^ user.cpp: In function ‘int main()’: user.cpp:85:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j; ^ user.cpp: In member function ‘void instream::advance()’: user.cpp:53:48: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,SIZE,1,input_file); ^ user.cpp: In function ‘int main()’: user.cpp:86:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("brazi.out","w",stdout); ^ user.cpp: In constructor ‘instream::instream(const char*)’: user.cpp:31:44: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,SIZE,1,input_file); ^