#include <iostream>
#include <fstream>

using namespace std;

int main()
{
	int datas[10];  
	int choose;
	int count = 0;

	while (1)
	{
		cout << "目前已經存了" << count << "個數字" << endl;
		cout << "1.新增一個數字 2.列出所有數字 3.更改某筆資料 4.清空所有資料 : ";
		cin >> choose;

		if (choose == 1)
		{
			int input;
			cout << "你要新增的數字 : ";
			cin >> input;

			datas[count] = input;
			++count;
		}
		else if (choose == 2)
		{
			cout << "目前已存的數字有 :";

			for (int i = 0; i < count; i++)
			{
				cout << datas[i] << ' ';;
			}

			cout << endl;
		}
		else if (choose == 3)
		{
			int input, newdata;

			cout << "你要修改第幾筆資料 : ";
			cin >> input;

			cout << "第" << input << "資料原本為" << datas[input] << endl;
			cout << "你想要改成 : ";
			cin >> datas[input];
		}
		else
		{
			count = 0;
		}
		cout << endl;
	}
}