Cutest bug you have ever seen?

[Joeman]

I was getting incorrect results although it was guaranted there should be no overflow for unsigned long long type. Still, result was incorrect. Find an error and get a rep point from me

I know!
this is pretty simple to me, but I am not a pro .

#include <iostream>
#include <string>

using namespace std;

int main()
{
	string s = "Testing";

	//iterate through string backwards
	for(size_t pos = s.length() - 1; ; --pos) {
		cout << s[pos] << endl;;
		if(pos == 0) break;

	}
}

#include <iostream>
#include <string>
#include <vector>
#include <numeric>
#include <algorithm>

using namespace std;

int main()
{
	vector<unsigned long long> vec;
	vec.push_back(123456789012LL);
	vec.push_back(987654321098LL);

	unsigned long long result = accumulate(vec.begin(), vec.end(), 0LL);
	cout << result;
}

Do you want an explanation too?