Compilare: main.cpp: In function 'int main()': main.cpp:69:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("huffman.in", "r", stdin); ^ main.cpp:70:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("huffman.out", "w", stdout); ^ main.cpp:72:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%ld", &N); ^ main.cpp:75:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%ld", &nodes[i].val); ^