Binary search question

2. Consider the array consisting of 7 elements sorted in ascending order.
What is the Maximum number of comparisons that need to be done to find any
given element using:


a. Sequential search (10 points)

b. Binary search (10 points)


Answer below:


a. Since the total number of elements is seven, and the value is unknown I
can only assume that the maximum number of comparisons may be the total
amount of elements, seven (7).


b. The binary search for any given number is what I can't figure out. I
have
attempted to use the following code and formula but am very confused as to
what the answer could be. I can get certain values but when I try for
example the number two as the value to search for it just doesn't work.


       low = 0
       high = N
       while (low < high) {
           mid = (low + high)/2;
           if (A[mid] < value)
               low = mid + 1;
           else
                //can't be high = mid-1: here A[mid] >= value,
                //so high can't be < mid if A[mid] == value
                high = mid;
       }
       if (low < N) and (A[low] == value)
           return low
       else
           return not_found


any help greatly appreciated.


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