#include <stdio.h>
void avlInsert(treePointer *parent, element x, int *unbalanced){
    if (!*parent){
        *unbalanced = TRUE;
        *parent = (treePointer)malloc(sizeof(treeNode));
        (*parent)->leftChild = (*parent)->rightChild=NULL;
        (*parent)->bf=0; (*parent)->data=x;
    }
    else if(x.key < (*parent)->data.key){
        avlInsert(&(*parent)->leftChild, x, unbalanced);
        if(*unbalanced)
        /* left branch has grown higher*/
            switch((*parent)->bf){
                case -1: (*parent)->bj= ㄱ;
                        *unbalanced=FALSE; break;
                case 0: (*parent)->bf= ㄴ; break;
                case 1: leftRotation(parent, unbalanced);
            }
    }
    ...하략...
} /*end of avlInsert*/