Median of an odd number of elements

The sorting program is ready and tested. Now let’s proceed to calculation of the median. For a sorted array with an odd number of elements, the median is the value of the middle element.

The median is less affected by extreme values than the average:

// Average: 3
[1, 2, 3, 4, 5]
// Median: 3
[1, 2, 3, 4, 5]

// Average: 12
[1, 2, 3, 4, 50]
// Median: 3
[1, 2, 3, 4, 50]

It is easy to calculate a median for an array with an odd number of elements. To do this, you need to correctly calculate the middle element’s index. Let’s try to derive the formula:

// Array length 3, middle element index 1
[1, 2, 3]

// Array length 5, middle element index 2
[1, 2, 3, 4, 5]

// Array length 7, middle element index 3
[1, 2, 3, 4, 5, 6, 7]

Let’s subtract one from the array length and divide it by two to get the index.

Muffin can send data arrays of different lengths, so you’ll have to check whether the number of elements is odd or even and, depending on the result, find the median. To check this, let’s use the operator we are already familiar with: %.