#include <stdio.h>
int main()
{
int a[] = {2, 4, 6, 8, 10};
int i, sum=0, *b=a+4; /* Here b points to the address of a[4]=10 */
/* *b means the value of which the address b points to. */
/* So *b = a[4] = 10 */
/* (b-1) means &a[4-1], so *(b-1)=a[4-1]=8 */
/* (b-2) means &a[4-2], so *(b-2)=a[4-2]=6 */
/* and so on. */
for (i=0; i<5; i++)
sum=sum+(*b-i)-*(b-i); /* sum=0+(10-0)-(10) = 0 */
/* sum=0+(10-1)-(8) = 1 */
/* sum=1+(10-2)-(6) = 3 */
/* sum=3+(10-3)-(4) = 6 */
/* sum=6+(10-4)-(2) = 10 */
printf("%d\n", sum); /* It will give the output as 10. */
return 0;
}
So the correct answer is $10$.