## diceSum2

Language/Type: C++ backtracking recursion
Author: Marty Stepp (on 2016/06/16)

Write a recursive function named `diceSum2` that is a variation of the previous problem, `diceSum`. Your function should accept two parameters: an integer representing a number of 6-sided dice to roll, and a desired sum, and output all possible combinations of values that could appear on the dice that would add up to exactly the given sum, showing only unique combinations of dice, ignoring order. For example, the call of `diceSum2(2, 7);` should print:

```{1, 6}
{2, 5}
{3, 4}
```

The call of `diceSum2(3, 7);` should print:

```{1, 1, 5}
{1, 2, 4}
{1, 3, 3}
{2, 2, 3}
```

If the number of digits passed is 0 or negative, or if the given number of dice cannot add up to exactly the given sum, print no output. Your function must use recursion, but you can use a single `for` loop if necessary.

Type your C++ solution code here:

This is a function problem. Write a C++ function as described. Do not write a complete program; just the function(s) above.