How to count nodes of a link list by using Recursion in C++

Question

I mean I want to use Recursion function to count nodes of a link list.

Vulpes · Answer

To move through a 'standard' linked list in C++ we need an iterator and we also need to know when the iteration will end because there are no more nodes. So initially we pass the counter function a pointer to the first node and also a pointer to the position just after the last node. The total number of nodes is 1 plus the number of nodes from the next position to the end. So we increment the pointer and call the counter function recursively until eventually we get to the end when the stack unwinds and we're left with 0 plus a series of 1's which add up to the number of nodes in the linked list.

Joe Wilson · Answer

Thank you for your answer and could you please explain this part of the project: I don't understand the codes below. int counter(list ::iterator pos list ::iterator end) { if(pos == end) return 0; return 1 + counter(++pos end); // recursive call }

Vulpes · Answer

Try this: #include #include using namespace std; int counter(list ::iterator pos list ::iterator end) { if(pos == end) return 0; return 1 + counter(++pos end); // recursive call } int main() { list numbers; list ::iterator pos; int number count i; char lr; cout cin >> count; cout for(i = 0; i { cout cin >> number; numbers.push_back(number); } cout cout for (pos = numbers.begin(); pos != numbers.end(); pos++) { cout } cout int size = counter(numbers.begin() numbers.end()); cout return 0; }