最大和“连续子序列”

#include <iostream>
#include <vector>
using namespace std;

int main()
{
    const int N = 1000;
    char str[N];
    int x;
    while(cin.getline(str, N))
    {
        vector<int> arr;
        istrstream iss(str, N);
        while(iss >> x )
        {
            arr.push_back(x);
        }

        int sum = 0;
        int max_sum = 0;
        int start = 0, start_old = 0, end = 0;
        for(int i = 0; i < arr.size(); ++i)
        {
            if(sum + arr[i] > 0)
            {
                sum += arr[i];
            }
            else
            {
                sum = 0;
                start_old = i + 1;
            }

            if(sum > max_sum)
            {
                max_sum = sum;
                start = start_old;
                end = i;
            }
        }

        cout << "max_sum: " << max_sum << endl;
        for(int i = start; i <= end && end < arr.size(); ++i)
        {
            cout << arr[i] << " ";
        }

        cout << endl;
    }

    return 0;
}

test：

1 3 5 -10 6 7 -2 8 -20 10 15 -2 5
max_sum: 28
10 15 -2 5