数据结构_C语言_二叉树先序、中序、后序遍历

# include <stdio.h>
# include <stdlib.h>

typedef struct BiTreeNode {
    char data;
    struct BiTreeNode * lchild;
    struct BiTreeNode * rchild;
}BTNode, * pBTNode;

pBTNode createBTree();
void assign(pBTNode * ppn, char data, pBTNode plc, pBTNode prc);
void PreTraverse(pBTNode pt);
void InTraverse(pBTNode pt);
void PostTraverse(pBTNode pt);

int main(void) {
    pBTNode root = createBTree();
//    printf("[root] data->%c    lchild->%d    rchild->%d    add=%d\n", root->data, root->lchild, root->rchild, root);

    printf("-PreTraverse-\n");
    PreTraverse(root);
    printf("\n");

    printf("-InTraverse-\n");
    InTraverse(root);
    printf("\n");

    printf("-PostTraverse-\n");
    PostTraverse(root);
    printf("\n");

    return 0;
}

pBTNode createBTree() {
    pBTNode p1 = (pBTNode)malloc(sizeof(BTNode));
    pBTNode p2 = (pBTNode)malloc(sizeof(BTNode));
    pBTNode p3 = (pBTNode)malloc(sizeof(BTNode));
    pBTNode p4 = (pBTNode)malloc(sizeof(BTNode));
    pBTNode p5 = (pBTNode)malloc(sizeof(BTNode));
    pBTNode p6 = (pBTNode)malloc(sizeof(BTNode));

    assign(&p1, '1', p2, p5);
    assign(&p2, '2', p3, p4);
    assign(&p3, '3', NULL, NULL);
    assign(&p4, '4', NULL, NULL);
    assign(&p5, '5', p6, NULL);
    assign(&p6, '6', NULL, NULL);
/*
    printf("[p1] data->%c    lchild->%d    rchild->%d    add=%d\n", p1->data, p1->lchild, p1->rchild, p1);
    printf("[p2] data->%c    lchild->%d    rchild->%d    add=%d\n", p2->data, p2->lchild, p2->rchild, p2);
    printf("[p3] data->%c    lchild->%d    rchild->%d    add=%d\n", p3->data, p3->lchild, p3->rchild, p3);
    printf("[p4] data->%c    lchild->%d    rchild->%d    add=%d\n", p4->data, p4->lchild, p4->rchild, p4);
    printf("[p5] data->%c    lchild->%d    rchild->%d    add=%d\n", p5->data, p5->lchild, p5->rchild, p5);
    printf("[p6] data->%c    lchild->%d    rchild->%d    add=%d\n", p6->data, p6->lchild, p6->rchild, p6);
*/
    return p1;
}

void assign(pBTNode * ppn, char data, pBTNode pl, pBTNode pr) {
    (*ppn)->data = data;
    (*ppn)->lchild = pl;
    (*ppn)->rchild = pr;
}

void PreTraverse(pBTNode pt) {
    if (pt == NULL) return;

    printf("%c\n", pt->data);
    PreTraverse(pt->lchild);
    PreTraverse(pt->rchild);
}

void InTraverse(pBTNode pt) {
    if (pt == NULL) return;

    InTraverse(pt->lchild);
    printf("%c\n", pt->data);
    InTraverse(pt->rchild);
}

void PostTraverse(pBTNode pt) {
    if (pt == NULL) return;

    PostTraverse(pt->lchild);
    PostTraverse(pt->rchild);
    printf("%c\n", pt->data);
}