编写一个C语言程序,实现二叉树的建立与遍历。遍历要求包括前序、中序、后序、层次遍历。
时间: 2024-05-07 16:15:50 浏览: 5
```c
#include <stdio.h>
#include <stdlib.h>
// 定义二叉树结构体
typedef struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
} TreeNode;
// 前序遍历
void preorderTraversal(TreeNode* root) {
if (root == NULL) {
return;
}
printf("%d ", root->val);
preorderTraversal(root->left);
preorderTraversal(root->right);
}
// 中序遍历
void inorderTraversal(TreeNode* root) {
if (root == NULL) {
return;
}
inorderTraversal(root->left);
printf("%d ", root->val);
inorderTraversal(root->right);
}
// 后序遍历
void postorderTraversal(TreeNode* root) {
if (root == NULL) {
return;
}
postorderTraversal(root->left);
postorderTraversal(root->right);
printf("%d ", root->val);
}
// 层次遍历
void levelorderTraversal(TreeNode* root) {
if (root == NULL) {
return;
}
TreeNode *queue[1000];
int front = 0, rear = 0;
queue[rear++] = root;
while (front != rear) {
TreeNode *node = queue[front++];
printf("%d ", node->val);
if (node->left != NULL) {
queue[rear++] = node->left;
}
if (node->right != NULL) {
queue[rear++] = node->right;
}
}
}
// 创建二叉树
TreeNode* createTree() {
int val;
scanf("%d", &val);
if (val == -1) {
return NULL;
}
TreeNode *root = (TreeNode*)malloc(sizeof(TreeNode));
root->val = val;
root->left = createTree();
root->right = createTree();
return root;
}
int main() {
TreeNode *root = createTree();
printf("前序遍历:");
preorderTraversal(root);
printf("\n中序遍历:");
inorderTraversal(root);
printf("\n后序遍历:");
postorderTraversal(root);
printf("\n层次遍历:");
levelorderTraversal(root);
printf("\n");
return 0;
}
```