Compilare: user.cpp: In function ‘int main()’: user.cpp:86:25: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(L, MAX_S, fin); ^ user.cpp: In function ‘node* eval(char*&, int)’: user.cpp:15:40: warning: ‘newParent’ may be used uninitialized in this function [-Wmaybe-uninitialized] left(l), right(r), op(o), val(v) {} ^ user.cpp:42:15: note: ‘newParent’ was declared here node *newParent; ^