Compilare: user.cpp: In function ‘int main()’: user.cpp:88:11: warning: variable ‘M’ set but not used [-Wunused-but-set-variable] int N, M, numEdges; ^ user.cpp:85:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("java.in", "rb", stdin); ^ user.cpp:86:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("java.out", "wb", stdout); ^ user.cpp: In function ‘char GetChar()’: user.cpp:18:39: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, BUFF_SIZE, stdin); ^