Compilare: user.cpp: In function ‘void revise(long int)’: user.cpp:48:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(long i=1;i<list[id].size();i++) ^ user.cpp: In function ‘void addGrade(long int)’: user.cpp:55:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(long i=0;i<list[id].size();i++) ^ user.cpp: In function ‘void sortTop()’: user.cpp:75:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(long i=0;i<list[node].size();i++){ ^ user.cpp: In function ‘int main()’: user.cpp:137:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(long j=0;j<list[node].size();j++){ ^ user.cpp:84:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("volum.in","r",stdin); ^ user.cpp:85:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("volum.out","w",stdout); ^ user.cpp:87:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld",&n,&m); ^ user.cpp:90:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&a[i][j]); ^ user.cpp:147:31: warning: ‘prov’ may be used uninitialized in this function [-Wmaybe-uninitialized] how[prov] += how[node]; ^