Okay, looks like a standard array. For your program, do the bubblesort like I hope is in your textbook; then you will have:

12 17 30 45 51 62

Do a for() loop, adding every other one.

Ex:
Code:
int iTotal = 0, i;
for(i = 0; i < 6; i += 2)
    iTotal += list[i];
 
printf("Total = %d\n", iTotal);