c# 二分查找

// perform a binary search on the data
public int BinarySearch( int searchElement )
{ private int[] data;
int low = 0; // low end of the search area
int high = data.Length - 1; // high end of the search area
int middle = ( low + high + 1 ) / 2; // middle element
int location = -1; // return value; -1 if not found

do // loop to search for element
{
// if the element is found at the middle
if ( searchElement == data[ middle ] )
location = middle; // location is the current middle

// middle element is too high
else if ( searchElement < data[ middle ] )
high = middle - 1; // eliminate the higher half
else // middle element is too low
low = middle + 1; // eliminate the lower half

middle = ( low + high + 1 ) / 2; // recalculate the middle
} while ( ( low <= high ) && ( location == -1 ) );

return location; // return location of search key
} // end method BinarySearch