二叉樹的 先序，中序，後序

#include<iostream>
using namespace std;
struct Node{
    int value;
    Node *left, *right;
};
class BT{
public:
    Node *root;
    BT(){
        root = NULL;
    }
    void insert(int value){
        if (root == NULL){
            root = new Node;
            root->value = value;
            root->left = NULL;
            root->right = NULL;
        }
        else
 
{
            Node *current = root;
            while (1){
                if (value < current->value){
                    if (current->left == NULL){
                        current->left = new Node;
                        current->left->value = value;
                        current->left->left = NULL;
                        current->left->right = NULL;
                        break
 
;
                    }
                    else{
                        current = current->left;
                        continue;
                    }
                }
                else{
                    if (current->right == NULL){
                        current->right = new Node;
                        current->right->value = value;
                        current->right->left = NULL;
                        current->right->right = NULL;
                        break
 
;
                    }
                    else{
                        current = current->right;
                        continue;
                    }
                }
            }


        }
    }
    void inorder(Node *current){
        if (current == NULL)
            return;
        inorder(current->left);
        cout << current->value << "\t";
        inorder(current->right);
    }
    void preorder(Node *current){
        if (current == NULL)
            return;
        cout << current->value << "\t";
        preorder(current->left);
        preorder(current->right);
    }
    void postorder(Node *current){
        if (current == NULL)
            return;
        postorder(current->left);
        postorder(current->right);
        cout << current->value << "\t";
    }
};
int main(){
    int mylist[] = { 4, 3, 1, 5, 8, 2 };
    BT *mytree = new BT();
    for (int i = 0; i < 6; i++){
        mytree->insert(mylist[i]);
    }
    mytree->inorder(mytree->root);
    cout << endl;
    mytree->preorder(mytree->root);
    cout << endl;
    mytree->postorder(mytree->root);
    char a;
    cin >> a;
}

一個隨機生成字母的c程式碼

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

int main()
{
    int i,n;
    printf("輸入字串長度：");
    scanf("%d",&n);

    char *buffer=(char*)malloc(n+1);
    if (buffer==NULL) exit(1);
    for (i=0;i<n;i++)
        buffer[i]=rand()%26+'A';
    buffer[n]='\0';
    printf("隨機生成的字串為：%s\n",buffer);
    free(buffer);
    system("pause");

    return 0;
}