Compilare: main.cpp: In function 'void fixTwoBlackCase(Node*, Node*)': main.cpp:253:25: warning: NULL used in arithmetic [-Wpointer-arith] if ((!S->right == NULL && S->right->color == RED) || (!S->left == NULL && S->left->color == RED)) { ^~~~ main.cpp:253:73: warning: NULL used in arithmetic [-Wpointer-arith] if ((!S->right == NULL && S->right->color == RED) || (!S->left == NULL && S->left->color == RED)) { ^~~~ main.cpp: In function 'Node* searchForNode(Node*, int)': main.cpp:420:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:423:36: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized] Node *N = searchForNode(root, key); ^ main.cpp:456:9: note: 'root' was declared here Node *root; ^~~~