Question

i. void insertAfter(listNode **listPtr, int findValue, int value);

Find the first node that contains the findValue and move the node from its current location to the head of the list.

This is in C language. This has been provided:

typedef struct listNode{

int value;

struct listNode *next;

} listNode;

Answer 1

void insertAfter(listNode** listPtr, int findValue, int value)
{
    listNode *position = *listPtr;                //listnode pointer to traverse list
    listNode *temp;                               //pointer to keep position of previous node
    temp = position;

    while (position != NULL)
    {
        if (position->value == findValue)
            break;

        temp = position;
        position = position->next;
    }

    if( temp == position )  //in case value already at head of list
    {
        cout<<"already at head";
    }
    else if (position==NULL )  // value not found
    {
        cout<< " value not found";
    }
    else if (position->next == NULL )     // if value is found at end of the list
    {
        position->next =  (*listPtr);
        (*listPtr) = position;
        temp->next = NULL;
    }
    else                            // if value found in middle
    {
        temp->next = position->next ;
        position->next =  (*listPtr);
        (*listPtr) = position;
    }

}