Reverse Linked List

We use Recursion to reverse singly linked list .

We can print 1 to 5 using recursion . Just making one line down we could print 5 to 1 .

Example -

void rec(int i, int n)
{
    // base case
    if (i == n)
        return;
cout << i << endl;

    rec(i + 1, n);

}
int main()
{
    int n = 5;
    rec(1, n);
}

Output - 1
2
3
4
5
If we just make down one line it will be reversed

void rec(int i, int n)
{
    // base case
    if (i == n)
        return;


    rec(i + 1, n);
    cout << i << endl;

}

So , Let's convert it to Linked List .....

In Linked List , For traversing we take tmp Node . We don't use head Node here . Ok?
Then what will be the base case ?
Guess.....

Think.....

Done?

if(tmp == NULL) {
return ;
}

Then how to call rec function ?

See the recursion function in the upper ?

What to write ?

Yeah , You guessed right

rec(tmp->next) ;
cout << tmp->val << endl ;

This is how we easily reversed linked list ....

include

using namespace std;

struct Node {
int val;
Node* next;
Node(int x) : val(x), next(NULL) {}
};

void reversePrint(Node* tmp) {
if (tmp == NULL) return;

reversePrint(tmp->next); // Recursive call
cout << tmp->val << " "; // Print after recursion

}

int main() {
Node* head = new Node(1);
head->next = new Node(2);
head->next->next = new Node(3);
head->next->next->next = new Node(4);
head->next->next->next->next = new Node(5);