Design a combinational $($complex$)$circuit for a four$-$bit $"2\text{'}$s complement" $($r complement$)$circuit$.($The output of the circuit produces the $2\text{'}$s complement of the input binary number $(0-1).)$Design and draw the circuit using Exclusive$-$OR $($XOR$)$gates$.$ If the circuit were five bits instead of four, can you predict what the output functions would be$?$What changes would be observed in the circuit for a $5-$bit input when generating the $2\text{'}$s complement?