Compilare: user.cpp: In function ‘int main()’: user.cpp:53:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<comp.size(); i++) ^ user.cpp:55:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<comp[i].size(); j++) printf("%d ",comp[i][j]); ^ user.cpp:40:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.in","r", stdin); ^ user.cpp:41:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.out","w", stdout); ^ user.cpp:43:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:46:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^