Eroare de compilare: user.cpp: In function ‘void sift(int)’: user.cpp:25:26: error: ‘N’ was not declared in this scope while(left_son(nod)<=N) ^ user.cpp:27:22: error: ‘k’ was not declared in this scope son=left_son(k); ^ user.cpp: In function ‘int main()’: user.cpp:34:16: warning: unused variable ‘x’ [-Wunused-variable] int n, op, x; ^