This is my code

#include
using namespace std;
class LL{

public:
int data;
LL *next;
LL(int d)
{
    data=d;
    next=NULL;
}

};

void push(LL *&head,int data)
{

    LL* temp = new LL(data); 
    temp->next = head; 
    head = temp; 
} 

void reversebyK(LL *&head,int K)
{

    int jump=1;
    LL *prev=NULL;
    LL *current=head;
    while(jump<=K-1)
    {
        prev=current;
        current=current->next;
        jump++;
    }
    head->next=current->next;
    current->next=prev;
    prev->next=head;

}
void print(LL *head)
{

    while(head!=NULL)
    {
        cout<<head->data<<"->";
        head=head->next;
    }

}
int main() {

LL *head=NULL;
push(head,4);
push(head,5);
push(head,8);
push(head,9);
push(head,3);
push(head,1);
push(head,2);
reversebyK(head,3);
print(head);

}