Final answer:
The problem with the recursive function is that it lacks a base case, leading to infinite recursion and potential stack overflow. To fix it, a base case should be added that stops the recursion when a certain condition is met.
Step-by-step explanation:
Understanding Recursive Functions
The problem with the provided recursive function void printnum(int n) is that it lacks a base case. Without a base case, the recursion will continue indefinitely, leading to a stack overflow error because printnum is called with a decremented value of n infinitely. A recursive function must have a base case to terminate, which is a condition under which it will not make a further call to itself and thus, will stop executing. For example, a base case for this function could be when n reaches a certain value, at which point the function would cease to call itself.
In the current form, the printnum function will print the values of n endlessly until the program crashes due to a stack overflow. To solve this problem, one must add a base case check at the beginning of the function, such as:
void printnum(int n) {
if(n <= 0) return; // Base case to stop the recursion
cout << n << endl;
printnum(n - 1);
}
With this modification, the function will stop calling itself once n is less than or equal to zero, thus preventing an infinite loop and a subsequent stack overflow.