Hi Friends,

I am trying to write a method to calculate the sum of the odd numbers in all the numbers less than the given number. so eg. CalcOdd(7) would return 5 + 3 + 1 = 9. CalcOdd (10) would return 9 + 7 + 5 + 3 + 1 = 25 etc

The method needs to take in a number, subtract 1, then recursively work backwards adding all odd numbers until it reaches 0. This is what I have so far.

private static int CalcOdd(int n)

if (n <= 1)
return 1;
if (n % 2 == 0)

return n + CalcOdd(n - 2);

It doesn't work so well, it includes the number passed in in the addition which is not what I want. Can anyone suggest a better way of doing this ? I would also loke to be able to port the answer to work for even numbers and add the option to include the original passed in number in the answer.

Many thanks