# include <stdio.h>
# include <malloc.h>struct BTNode
{int data;struct BTNode * pLchild; // p 是指针   L 是左   child 是孩子struct BTNode * pRchild; // 表示右孩子
};struct BTNode * CreateBTree(void); //静态创建二叉树
void PreTraverseBTree(struct BTNode * pT); //先序遍历
void InTraverseBTree(struct BTNode * pT); //中序遍历
void PostTraverseBTree(struct BTNode * pT); //后续遍历int main(void)
{BTNode pT = CreateBTree(); //这里不能加 void
    PreTraverseBTree(pT); //先序遍历InTraverseBTree(pT); //中序遍历PostTraverseBTree(pT); //后续遍历return 0;
}void PostTraverseBTree(struct BTNode * pT) //后续遍历
{if (pT != NULL){if (NULL != pT->pLchild){PostTraverseBTree(pT->pLchild); // pT->pLchild可以代表整个左子树
        }if (NULL != pT->pRchild){PostTraverseBTree(pT->pRchild);}printf("%c\n", pT->data);}
}void InTraverseBTree(struct BTNode * pT) //中序遍历
{if (pT != NULL){if (NULL != pT->pLchild){InTraverseBTree(pT->pLchild); // pT->pLchild可以代表整个左子树
        }printf("%c\n", pT->data);if (NULL != pT->pRchild){InTraverseBTree(pT->pRchild);}}
}void PreTraverseBTree(struct BTNode * pT) //先序遍历
{if (pT != NULL){printf("%c\n", pT->data);if (NULL != pT->pLchild){PreTraverseBTree(pT->pLchild); // pT->pLchild可以代表整个左子树
        }if (NULL != pT->pRchild){PreTraverseBTree(pT->pRchild);}} // if 判断不能省略/*   //伪算法先访问跟节点再先序访问左子树在先序访问右子树
*/
}struct BTNode * CreateBTree(void)
{struct BTNode pA = (struct BTNode *)malloc(sizeof(struct BTNode));struct BTNode pB = (struct BTNode *)malloc(sizeof(struct BTNode));struct BTNode pC = (struct BTNode *)malloc(sizeof(struct BTNode));struct BTNode pD = (struct BTNode *)malloc(sizeof(struct BTNode));struct BTNode pE = (struct BTNode *)malloc(sizeof(struct BTNode));pA->data = 'A';pB->data = 'B';pC->data = 'C';pD->data = 'D';pE->data = 'E';pA->pLchild = pB;pA->pRchild = pC;pB->pLchild = pB->pRchild = NULL;pC->pLchild = pD;pC->pRchild = NULL;pD->pLchild = NULL;pD->pRchild = pE;pE->pLchild = pE->pRchild = NULL;return pA;
}