Compilare: user.cpp: In function ‘void df(int, bool)’: user.cpp:26:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a[x].size(); i++) { ^ user.cpp: In function ‘void dff(int)’: user.cpp:46:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a[x].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:80:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a[x].size(); i++) { ^ user.cpp:92:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < a[x].size(); j++) { ^ user.cpp:57:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("symmetricgraph2.in", "r", stdin); ^ user.cpp:58:48: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("symmetricgraph2.out", "w", stdout); ^ user.cpp:60:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:62:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &C); ^