$1//$ Ex$.7\mathrm{.}18$: Ex$07\_18.$cpp

$2//$ What does this program do$?$

$3$ #include

$4$ using namespace std;

$5$

$6$ int whatIsThis$($ int $[],$ int $)$; $//$ function prototype

$7$

$8$ int main$()$

$9\{$

$10$ const int arraySize $=10$;

$11$ int a$[$ arraySize $]=\{1,2,3,4,5,6,7,8,9,10\}$;

$12$

$13$ int result $=$ whatIsThis$($ a$,$ arraySize $)$;

$14$

$15$ cout $<<$ "Result is $"<<$ result $<<$ endl;

$16\}//$ end main

$17$

$18//$ What does this function do$?$

$19$ int whatIsThis$($ int b$[],$ int size $)$

$20\{$

$21$ if $($ size $==1)//$ base case

$22$ return b$[0]$;

$23$ else $//$ recursive step

$24$ return b$[$ size $-1]+$ whatIsThis$($ b$,$ size $-1)$;

$25\}//$ end function whatIsThis