library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;

entity fourmux2 is
  port(
       s:in integer range 0 to 1;
      a,b:in integer range 0 to 15;          
         fout:out integer range 0 to 15
); 
end;

architecture a of fourmux2 is
begin
 process(s)
begin
 if(s=0)then fout<=a;
else fout<=b;
end if;
end process;
end;