Compilare: user.cpp: In function ‘char nextch()’: user.cpp:20:33: 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, B, stdin); ^ user.cpp: In function ‘int main()’: user.cpp:143:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("treemis.in", "r", stdin); ^ user.cpp:144:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("treemis.out", "w", stdout); ^ user.cpp: In function ‘void dfs(int, int)’: user.cpp:122:27: warning: ‘mxtree’ may be used uninitialized in this function [-Wmaybe-uninitialized] swap(mx[mxtree], mx[u]); ^