Compilare: main.cpp: In function 'void huffman()': main.cpp:44:13: warning: unused variable 'cost' [-Wunused-variable] long long cost=0; ^~~~ main.cpp: In function 'int main()': main.cpp:81:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("huffman.in","rt",stdin); ^ main.cpp:82:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("huffman.out","wt",stdout); ^ main.cpp:84:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ main.cpp:89:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&f); ^