Prob $1.(20$ points total, $\frac{8}{12})$ Assume $A$ is a uint$16\_$t variable, written as $0x_3{H}_2{H}_1{H}_0,$ intended to

express an arbitrary number in hexadecimal format. Here $H_k$ is the $k$ th hexadecimal digit written in the normal

way where the right bit is the least significant bit. Write the $C$ code to perform the following operations to

change the digit $(4$ bits$)$ of interest without affecting the other digits $($bits$)$ or shift the number:

$($a$).A=0x{H}_3{H}_2{H}_1{H}_0=>A=A=0x{H}_2{H}_1{H}_{0}5$

$($b$).A=0H_3{H}_2{H}_1{H}_0=>A=0x_1{H}_0{H}_3{H}_2$