二叉樹的中序輸出求救

字號(hào)： 小 中 大

這個(gè)程序的思路是自己輸入數(shù)字,在輸入的同時(shí),已經(jīng)幫你左右順序排好了,即左子樹的數(shù)字比右子樹小,是個(gè)順序二叉樹,以輸入0為結(jié)素,而后一中序遍歷輸出,但不知道為什么,在屏幕上打引的卻是左子樹最小的數(shù)字,而且一直輸出,請(qǐng)看下面程序
    #include
    #include
    typedef struct no
    {
    int key;
    struct no *left,*right;
    }node,*PNOD;
    void inster(PNOD *p,int k)
    {
    PNOD ppre,pre,temp;
    ppre=*p;
    printf("current number ppre % d",ppre->key);
    if(ppre==NULL)
    {
    ppre=(node *)malloc(sizeof(node));
    ppre->key=k;
    ppre->left=NULL;
    ppre->right=NULL;
    *p=ppre;
    return;
    }
    while(ppre)
    {
    if(k < ppre->key)
    {
    temp=ppre;
    ppre=ppre->left;
    printf("left\n");
    }
    else if(k == ppre->key)
    {
    printf("has ...\n");
    return;
    }
    else if(k > ppre->key)
    {
    temp=ppre;
    ppre=ppre->right;
    printf("right\n");
    }
    /*printf("aaaaaaaaaaaaaaaaaa");*/
    }
    pre=(node *)malloc(sizeof(node));
    pre->key=k;
    pre->left=NULL;
    pre->right=NULL;