Please explain the logic behind this to me if you can supply the pseudo code too please

it is a Java recursive program to add two linked lists can you highlight where recursion is taking place

public class linkedlistATN { class node { int val; node next;

public node(int val) { this.val = val; } } // Function to print linked list void printlist(node head) { while (head != null) { System.out.print(head.val + " "); head = head.next; } }

node head1, head2, result; int carry;

/* A utility function to push a value to linked list */ void push(int val, int list) { node newnode = new node(val); if (list == 1) { newnode.next = head1; head1 = newnode; } else if (list == 2) { newnode.next = head2; head2 = newnode; } else { newnode.next = result; result = newnode; }

}

// Adds two linked lists of same size represented by // head1 and head2 and returns head of the resultant // linked list. Carry is propagated while returning // from the recursion void addsamesize(node n, node m) { // Since the function assumes linked lists are of // same size, check any of the two head pointers if (n == null) return;

// Recursively add remaining nodes and get the carry addsamesize(n.next, m.next);

// add digits of current nodes and propagated carry int sum = n.val + m.val + carry; carry = sum / 10; sum = sum % 10;

// Push this to result list push(sum, 3);

}

node cur;

// This function is called after the smaller list is // added to the bigger lists's sublist of same size. // Once the right sublist is added, the carry must be // added to the left side of larger list to get the // final result. void propogatecarry(node head1) { // If diff. number of nodes are not traversed, add carry if (head1 != cur) { propogatecarry(head1.next); int sum = carry + head1.val; carry = sum / 10; sum %= 10;

// add this node to the front of the result push(sum, 3); } }

int getsize(node head) { int count = 0; while (head != null) { count++; head = head.next; } return count; }

// The main function that adds two linked lists // represented by head1 and head2. The sum of two // lists is stored in a list referred by result void addlists() { // first list is empty if (head1 == null) { result = head2; return; }

// first list is empty if (head2 == null) { result = head1; return; }

int size1 = getsize(head1); int size2 = getsize(head2);

// Add same size lists if (size1 == size2) { addsamesize(head1, head2); } else { // First list should always be larger than second list. // If not, swap pointers if (size1 < size2) { node temp = head1; head1 = head2; head2 = temp; } int diff = Math.abs(size1 - size2);

// move diff. number of nodes in first list node temp = head1; while (diff-- >= 0) { cur = temp; temp = temp.next; }

// get addition of same size lists addsamesize(cur, head2);

// get addition of remaining first list and carry propogatecarry(head1); } // if some carry is still there, add a new node to // the front of the result list. e.g. 999 and 87 if (carry > 0) push(carry, 3); }

// Driver program to test above functions public static void main(String args[]) { linkedlistATN list = new linkedlistATN(); list.head1 = null; list.head2 = null; list.result = null; list.carry = 0; int arr1[] = { 9, 9, 9 }; int arr2[] = { 1, 8 };

// Create first list as 9->9->9 for (int i = arr1.length - 1; i >= 0; --i) list.push(arr1[i], 1);

// Create second list as 1->8 for (int i = arr2.length - 1; i >= 0; --i) list.push(arr2[i], 2);

list.addlists();

list.printlist(list.result); } }