Given one array, and calculate its maximum sum from any sequential subarray set

Cpp code demo as below:

1 int maxSubarraySum(int arr[], int length, int& beg, int& end) 2 { 3     assert(arr!=0); 4     int maxSum = 0; 5     int tmpSum = 0; 6     beg = 0; end = 0; 7     for (int i = 0; i < length; i++) { 8         tmpSum += arr[i]; 9         if (tmpSum < 0) {   // discard it10             tmpSum = 0;11             beg = end = i+1;12         }13         if (tmpSum > maxSum) {14             maxSum = tmpSum;15             end = i+1;16         }17     }18     if (maxSum ==0 ) {      // if all numbers are negative, return max value19         maxSum = arr[0];20         for (int i = 1; i < length; i++)21             if (maxSum < arr[i]) {22                 maxSum = arr[i];23                 beg = i; end = i+1;24             }25     }26     return maxSum;27 }28