Find the largest value smaller than x in a sorted array

Question

Suppose I have a sorted array of integers int[], and I want to search the closest smaller value to some input number.

for example if the array contains (1)

Answer 1

int getIndex( long[] list, long value )
{
    int top = 0;
    int bot = list.length-1;
    int mid=0;
    while ( top <= bot )
    {
        mid = (top+bot)/2; // NB integer arithmetic
        if ( value < list[mid] )
        {
            if ( mid == 0 )
                // value < than first item
                return -1;  
            else
                bot = mid-1;
        }
        else    // value >= list[mid]
        {
            if ( mid == list.length-1 )
                // value is >= last item
                break;
            else if ( value >= list[mid+1] )
                top = mid+1;
            else // list[mid] must be biggest <= value
                break;
        }
    }
    return mid;
}