Compilare: user.cpp: In function ‘void FirstDFS(int)’: user.cpp:17:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<g[index].size();i++) ^ user.cpp: In function ‘void SecondDFS(int)’: user.cpp:28:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<g[index].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:71:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<cycles.size();i++){ ^ user.cpp:75:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<lines.size();j++) ^ user.cpp:78:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<columns.size()-1;j++) ^ user.cpp:50:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("transform2.in","r",stdin); ^ user.cpp:51:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("transform2.out","w",stdout); ^ user.cpp:53:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:58:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^