Let us assume a file of 5 records that means n = 5

And k is a sorted array of keys of those 5 records.

Let key = 55, low = 0, high = 4

Iteration 1: mid = (0+4)/2 = 2 k(mid) = k (2) = 33

Now key > k (mid)

Thus low = mid + 1 = 3

Iteration 2: low = 3, high = 4 (low <= high)

Mid = 3+4 / 2 = 3.5 ~ 3 (integer value)

 Here key > k (mid)

Thus low = 3+1 = 4

Iteration 3: low = 4, high = 4 (low<= high)

Mid = (4+4)/2 = 4

Here key = k(mid)

Thus, the record is at mid+1 position that means 5