Compilare: user.cpp: In function ‘int main()’: user.cpp:26:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sons[nd].size();i++) ^ user.cpp:33:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<nivel[i].size();j++) ^ user.cpp:39:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(l=0;l<sons[nivel[i][j]].size();l++) ^ user.cpp:9:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("iepuri2.in","r",stdin); ^ user.cpp:10:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("iepuri2.out","w",stdout); ^ user.cpp:11:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^ user.cpp:14:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^