Sum of numbers in prime indexes using c#

Question

If the input is {2,3,10,15,11,19} then the output should be 44.
We know that the prime numbers are 2,3,5,7 and so on.
Here in index number
2 we have 10,
3 we have 15,
5 we have 19
Now the sum of those numbers is 10+15+19=44.

Answer 1

int[] arr = {...}
int size = arr.Length;
First you'll have to generate the primes number from 0 to size (excluding) and store them in a list called primes. (you do this part yourself :D)
int sum = 0;
foreach(int p in primes)
sum += arr[p];
Console.WriteLine(sum);

Answer 2

So question solved?
(if you want to generate primes, search for codes on SoloLearn or Google)

Answer 3

Thanks for ur great advice... Already I did that

Answer 4

I described it clearly na....
The numbers which are existing in the prime indexes... of that array should be added

Answer 5

That is vat the logic I'm asking... I too know the thing you typed

Answer 6

A={2,3,10,15,11,19}
A[2]=10, A[3] =15, A[5] =19....
add those numbers 10,15,19 and the output is 44
The index numbers 2,3,5 are primes.