View difference between Paste ID: 0rB1bxPV and W5DLigh4

-library ieee;
+
-use ieee.std_logic_1164.all;
+library IEEE;
 use IEEE.STD_LOGIC_1164.ALL;
-
+use IEEE.STD_LOGIC_ARITH.ALL;
 use IEEE.STD_LOGIC_UNSIGNED.ALL;
-port(
+
-a: in std_logic;
+
-b: in std_logic;
+Port ( a,b,S : in std_logic;
-S: in std_logic;
+O : out std_logic;
-O: out std_logic;
+
-);
+
 architecture Behavioral of MUX_2_1 is
-
+
 if (S='0') then
 	O <= a;
-with S select O <= a when '0', b when '1';
+else
 	O <= b;
 end if;
 
 end Behavioral;