How do I insert a node at the beginning of a linked list?

问题

What is wrong with addAtBegin? The list seems to be correct after assigning the newly created node to start, but when control returns to main, the new value is not saved.

typedef struct node
{
    int data;
    struct node *link;
}node;

node* createList(int data)
{
    node *tempNode=(node*)malloc(sizeof(node));
    tempNode->data=data;
    tempNode->link=NULL;
    return tempNode;
}

void addAtBegin(node *start,int data)
{
    node *addedNode=(node *)malloc(sizeof(node));
    addedNode->data=data;
    addedNode->link=(start==NULL)?NULL:start;
    start=addedNode;
}

void displayNodes(node *start)
{
    node *startCopy=start;
    while(startCopy!=NULL)
    {
        printf("%d\t",startCopy->data);
        startCopy=startCopy->link;
    }
    printf("\n");
}

int main( )
{   
    node *start=createList(2);
    addAtBegin(start,1);
    displayNodes(start);
    return 0;
}

回答1:

Looks like another list question to me, with the same answer as most of them - start should be a pointer to a pointer.

来源：https://stackoverflow.com/questions/1989185/how-do-i-insert-a-node-at-the-beginning-of-a-linked-list