Compilare: main.cpp: In function 'bool Is_Element_Hash_Table(Node**, int)': main.cpp:64:6: warning: unused variable 'key' [-Wunused-variable] int key = requested_element % HASH_TABLE_SIZE; ^~~ main.cpp: In function 'int main()': main.cpp:20:38: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for (fscanf(f, "%d", &no_operations);no_operations; no_operations--) { ^ main.cpp:21:60: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d", &operation_choice, &no_requested_user); ^