如何根据用户输入多次运行此代码？

Question

这是我的代码。它应该取一个数字（n）并计算1到n之间所有整数的总和。该部分代码工作正常。不起作用的是可以选择再次运行代码的部分。我正在尝试做的是提示用户最后输入Y或N。如果用户输入Y，则应将布尔变量设置为true，以使代码再次运行。当我尝试运行它时，会告诉我“ Y”和“ y”是未识别的标识符和未声明的标识符。

#include <iostream>
#include<string>
using namespace std;
int main()
{
    int n; 
    int sum = 0;
    int sum_helper;
    int n_original;
    string goagainstr;
    bool goagainbool;
    do
    {
        cout << "Enter a positive integer: ";
        cin >> n;
        n_original = n;
        if (n <= 0)
        {
            do
            {
                cout << "I said enter a POSITIVE integer: ";
                cin >> n;
            } while (n <= 0);
        }
        if (n > 0)
        {
            do
            {
                sum_helper = n;
                sum = sum + sum_helper;
                n = n - 1;
            } while (n != 0);
            cout << "The sum of all the integers from 1 up to "; cout << n_original; cout << " is "; cout << sum; cout << ". ";
            }
        cout << "Do you want to enter another number?(Y/N)";
        getline(cin, goagainstr);
            if (goagainstr==Y||goagainstr==y)
            {
                goagainbool = true;
            }
    } while (goagainbool == true);
    return 0;
}