Q$3.($a$)($i$)$ Describe the purpose of the following C function. Explain your answer carefully. int f$($int n$)\{$ int s $=0$; while $($n $>0)\{$ s $+=$ n$\%10$; n $/=10$; $\}$ return $($s$)$; $\}($ii$)$ Rewrite the following function using a while loop in place of the for loop. What is the purpose of the function? int func$($int $*$x$,$ int n$)\{$ int i$,$ y; y $=$ x$[0]$; for $($i$=1$; i y$)$ y $=$ x$[$i$]$; return$($y$)$; $\}(30\%)($b$)$ Explain what is meant by type definition and enumeration types in C$,$ with reference to the following line of C code: typedef enum$\{$DEC$,$ NOV, OCT, SEP, AUG, JUL, JUN, MAY, APR, MAR, FEB, JAN$\}$ Month; Write a function in C which takes in a single input argument of type Month $($as defined above$)$ and returns as output the number of days in that month. Note that the number of days in each month is given by: February: $28$ days January, March, May, July, August, October, December: $31$ days April, June, September, November: $30$ days