用C语言写一个红黑树的前中后序排列

红黑树是一种自平衡二叉查找树，它的前序、中序以及后序遍历与普通的二叉查找树遍历方式相同。下面是使用C语言实现红黑树的前序、中序以及后序遍历的代码。

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

typedef struct rb_node {
    int key;
    int color;
    struct rb_node *left, *right, *parent;
} rb_node;

void left_rotate(rb_node **root, rb_node *x) {
    rb_node *y = x->right;
    x->right = y->left;
    if (y->left != NULL) y->left->parent = x;
    y->parent = x->parent;
    if (x->parent == NULL) *root = y;
    else if (x == x->parent->left) x->parent->left = y;
    else x->parent->right = y;
    y->left = x;
    x->parent = y;
}

void right_rotate(rb_node **root, rb_node *y) {
    rb_node *x = y->left;
    y->left = x->right;
    if (x->right != NULL) x->right->parent = y;
    x->parent = y->parent;
    if (y->parent == NULL) *root = x;
    else if (y == y->parent->left) y->parent->left = x;
    else y->parent->right = x;
    x->right = y;
    y->parent = x;
}

void rb_insert_fixup(rb_node **root, rb_node *z) {
    while (z->parent != NULL && z->parent->color == 1) {
        if (z->parent == z->parent->parent->left) {
            rb_node *y = z->parent->parent->right;
            if (y != NULL && y->color == 1) {
                z->parent->color = 0;
                y->color = 0;
                z->parent->parent->color = 1;
                z = z->parent->parent;
            } else {
                if (z == z->parent->right) {
                    z = z->parent;
                    left_rotate(root, z);
                }
                z->parent->color = 0;
                z->parent->parent->color = 1;
                right_rotate(root, z->parent->parent);
            }
        } else {
            rb_node *y = z->parent->parent->left;
            if (y != NULL && y->color == 1) {
                z->parent->color = 0;
                y->color = 0;
                z->parent->parent->color = 1;
                z = z->parent->parent;
            } else {
                if (z == z->parent->left) {
                    z = z->parent;
                    right_rotate(root, z);
                }
                z->parent->color = 0;
                z->parent->parent->color = 1;
                left_rotate(root, z->parent->parent);
            }
        }
    }
    (*root)->color = 0;
}

void rb_insert(rb_node **root, int key) {
    rb_node *z = (rb_node*) malloc(sizeof(rb_node));
    z->key = key;
    z->color = 1;
    z->left = NULL;
    z->right = NULL;
    z->parent = NULL;
    rb_node *y = NULL;
    rb_node *x = *root;
    while (x != NULL) {
        y = x;
        if (z->key < x->key) x = x->left;
        else x = x->right;
    }
    z->parent = y;
    if (y == NULL) *root = z;
    else if (z->key < y->key) y->left = z;
    else y->right = z;
    rb_insert_fixup(root, z);
}

void inorder(rb_node *root) {
    if (root != NULL) {
        inorder(root->left);
        printf("%d ", root->key);
        inorder(root->right);
    }
}

void preorder(rb_node *root) {
    if (root != NULL) {
        printf("%d ", root->key);
        preorder(root->left);
        preorder(root->right);
    }
}

void postorder(rb_node *root) {
    if (root != NULL) {
        postorder(root->left);
        postorder(root->right);
        printf("%d ", root->key);
    }
}

int main() {
    rb_node *root = NULL;
    rb_insert(&root, 10);
    rb_insert(&root, 20);
    rb_insert(&root, 30);
    rb_insert(&root, 100);
    rb_insert(&root, 90);
    rb_insert(&root, 40);
    rb_insert(&root, 50);
    rb_insert(&root, 60);
    printf("Inorder Traversal: ");
    inorder(root);
    printf("\n");
    printf("Preorder Traversal: ");
    preorder(root);
    printf("\n");
    printf("Postorder Traversal: ");
    postorder(root);
    printf("\n");
    return 0;
}

以上代码包含了红黑树的插入操作和三种不同的遍历方式的实现。在代码中，`rb_insert()` 函数用于插入新节点，`inorder()` 函数、`preorder()` 函数和 `postorder()` 函数分别用于实现中序、前序和后序遍历。