Write a basic recursive function that sums all numbers from $1$ to n

Please write a simple recursive method recursiveAdd$()$ that adds all integers between the $1$ and the input number.

Your method should return the result as an integer.

In the event of a zero or negative input your method should return $0.$

Remember, you must have a halting condition so that the recursive function doesn't hang the program.

Recursive functions are useful anytime you must use a previous result of the algorithm for the next iteration of the algorithm.