Chapter 20, Problem 12RQE

#include <iostream>

using namespace std;

int function(int);

int main()

{

int x = 10;

cout ≪ function(x) ≪ endl;

return 0;

}

int function(int num)

{

if (num <= 0)

return 0;

else

return function(num − 1) + num;

}