Compilare: user.cpp: In function ‘int a4(trie*, char*, int)’: user.cpp:61:22: warning: left operand of comma operator has no effect [-Wunused-value] return (nod->p[ch],c+1,k+1); ^ user.cpp:61:25: warning: right operand of comma operator has no effect [-Wunused-value] return (nod->p[ch],c+1,k+1); ^ user.cpp: In function ‘int main()’: user.cpp:66:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.in","r",stdin); ^ user.cpp:67:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.out","w",stdout); ^ user.cpp:68:25: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(line,32,stdin); ^ user.cpp:81:29: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(line,32,stdin); ^