樹

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

struct node{
char data;

struct node* left;
struct node* right;
};

void preorder(struct node* root) //前序遍歷
{
if(root == NULL)
return ;
else {
printf("%c\t", root->data);
pre_order(root->left);
pre_order(root->right);

}
}
void minorder(struct node* root) //中序遍歷
{
if(root == NULL)
return ;
else {
min_order(root->left);
printf("%c\t", root->data);
min_order(root->right);
}
}
void postorder(struct node* root) //後序遍歷
{
if(root == NULL)
return ;
else {
postorder(root->left);
postorder(root->right);
printf("%c\t", root->data);
}
}
struct node* create(struct node* root) //利用前序創建樹，中序和後序不能創建樹
{
char ch = getchar();
if(ch == ‘#‘)
return NULL;
else {
root = malloc(sizeof(struct node));
root->data = ch;
root->left = create(root->left);
root->right = create(root->right);
return root;
}
}

int main()
{
struct node* root = NULL;

root = create(root);

preorder(root);
printf("\n");
minorder(root);
printf("\n");
postorder(root);
printf("\n");

return 0;
}

樹的創建和遍歷