Needing help with passing numbers

[Beginner to C pp]

I am currently working on a little program that will take a positive number and add it to the previous number while keeping a running total. The exit is to input a non positive number. I have everything worked out but for some reason I cannot figure out why my new total will not output the previous total plus the next number typed in. Any help is appreciated.

  #include <iostream>

using namespace std;

int main ()
{
	int startnum = 0;
	int nextnum;
	int posnum;

		cout << "Enter a positive number ";

	cin >> posnum;

		cout << "Your new total is " << startnum + posnum << endl;

	while (posnum >= 0)
	{
	cout << "Please enter another positive number " << endl;
	cin >> nextnum;
	cout << "Your new total is " << posnum + nextnum << endl;
	}

		cout << endl;
		cout << "That was a negative number " << endl;
		cout << endl;

	return 0;
}

[Stewbond]

Have you learned break; yet? Also it's because you don't add the nextnum into the running total, you just display it, then loose it.

#include <iostream>

using namespace std;

int main ()
{
	int startnum = 0;
	int nextnum;

	while (true)
	{
		cout << "Please enter a number " << endl;
		cin >> nextnum;

		if (nextnum < 0)
			break;
		
		startnum += nextnum;
		cout << "Your new total is " << startnum << endl;
	}

	cout << endl;
	cout << "That was a negative number " << endl;
	cout << endl;

	return 0;
}