Compilare: user.cpp: In function ‘void baga(Trie*, char*)’: user.cpp:55:16: warning: NULL used in arithmetic [-Wpointer-arith] if ( *s == NULL ) { ^ user.cpp: In function ‘int main()’: user.cpp:93:23: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] sir [ l + 1 ] = NULL ; ^ user.cpp:108:19: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] sir [ 0 ] = NULL ; ^ user.cpp:110:19: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] sir [ 0 ] = NULL ; ^