C++ HW9-1 for WallPower

將好友資料儲存到Friend資料結構，輸入時新增該筆資料到檔案，輸出時從檔案印出。
參考輸出如下。

#include <iostream>
#include <string>
#include <fstream>
using namespace std;

struct Data
{
 string  name, phone, bitthday;
};

Data ReadData();
void SaveFile(Data _Data, string Filepath);
void ShowData(string FilePath);
string FilePath = "\FriendData.txt";
int select = 0;

int main()
{
 while (1)
 {
  cout << "請問您要 1)輸出好友名單 2)新增好友資料：";
  cin >> select;
  if (select == 1)
   ShowData(::FilePath);
  else if (select == 2)
   SaveFile(ReadData(), ::FilePath);
 }
 return 0;
}

Data ReadData()
{
 Data temp;
 cout << "請輸入名稱：";
 cin >> temp.name;
 cout << "請輸入電話號碼：";
 cin >> temp.phone;
 cout << "請輸入生日：";
 cin >> temp.bitthday;
 return temp;
}

void SaveFile(Data _Data, string FilePath)
{
 fstream fs(FilePath, ios::app);
 fs << _Data.name << "\n";
 fs << _Data.phone << "\n";
 fs << _Data.bitthday << "\n";
 fs.close();
}

void ShowData(string FilePath)
{
 fstream fs(FilePath);
 string name;
 string phone;
 string birthday;
 while (!fs.eof())
 {
  getline(fs, name, '\n');
  getline(fs, phone, '\n');
  getline(fs, birthday, '\n');
  if (name == "")
   break;
  cout << "==============================================" << endl;
  cout << name << "的電話：" << phone << endl;
  cout << name << "的生日：" << birthday << endl;
 }
 fs.close();
}