write code vhdl cruise control how ???

I search many website try Execution code is same problem:(:confused:

----- File project.vhd: ---------------------
2 LIBRARY ieee;
3 USE ieee.std_logic_1164.all;
4 ------------------------------------
5 ENTITY project IS
6 PORT (a, b, c, d: IN STD_LOGIC;
7 x, y: OUT STD_LOGIC);
8 END project;
9 ------------------------------------
10 ARCHITECTURE structural OF project IS
11 -------------
12 COMPONENT inverter IS
13 PORT (a: IN STD_LOGIC; b: OUT STD_LOGIC);
14 END COMPONENT;
15 -------------
16 COMPONENT nand_2 IS
17 PORT (a, b: IN STD_LOGIC; c: OUT STD_LOGIC);
18 END COMPONENT;
19 -------------
20 COMPONENT nand_3 IS
21 PORT (a, b, c: IN STD_LOGIC; d: OUT STD_LOGIC);
22 END COMPONENT;
23 -------------
24 SIGNAL w: STD_LOGIC;
25 BEGIN
26 U1: inverter PORT MAP (b, w);
27 U2: nand_2 PORT MAP (a, b, x);
28 U3: nand_3 PORT MAP (w, c, d, y);
29 END structural;

Error: Node instance "U1" instantiates undefined entity "inverter"
Error: Node instance "U2" instantiates undefined entity "nand_2"
Error: Node instance "U3" instantiates undefined entity "nand_3"
Error: Quartus II Analysis & Synthesis was unsuccessful. 3 errors, 0 warnings
Error: Quartus II Full Compilation was unsuccessful. 5 errors, 0 warnings