Compilare: user.cpp: In function ‘int main()’: user.cpp:56:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<comp.size();i++) ~^~~~~~~~~~~~ user.cpp:58:16: 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:43:35: 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:44:37: 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:46:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:49:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^