[PTA] 数据结构与算法题目集 6-11 先序输出叶结点

//函数PreorderPrintLeaves应按照先序遍历的顺序输出给定二叉树BT的叶结点，格式为一个空格跟着一个字符。
void PreorderPrintLeaves(BinTree BT)
{
    if (BT == NULL)
        return;
    if (BT->Left == NULL && BT->Right == NULL)
        printf(" %c", BT->Data);
    PreorderPrintLeaves(BT->Left);
    PreorderPrintLeaves(BT->Right);
}