How to combine two arrays of integers and return average?

Question

Ok so I have two arrays of integers, and I have to return the average rating of the two days. This is the code that I have come up with thus far, but apparently it does not meet the expectations. Result:

Message: Expected: 5.0d But was: 3.0d

Unit:

public double WeekendAverage(int[] saturday, int[] sunday)
    {
        int[] n = { saturday.Length, sunday.Length };
        int sum = 0;

        for (int i = 0; i < n.Length; i++)
        {
            sum = saturday[i] + sunday[i];
            return sum / n.Length;
        }
        return sum;
        }

UnitTest:

[TestCase(new[] { 1, 2, 3, 4, 5, 7, 8, 5, 10 }, new[] { 9, 9, 9, 8, 9, 8, 9, 9, 9, 10, 10 }, 7)]

public void WeekendAverage(int[] saturday, int[] sunday, double expected)
    {
        var actual = warmups.WeekendAverage(saturday, sunday);
        Assert.AreEqual(expected, actual);
    }

There are multiple problems in your code. Array n in your code will have only two values, length of Saturday array and length of Sunday array. It will not have the actual values from Saturday and Sunday. Also you are returning from for loop so the loop will be executed only once. You need make the logic clear and debug the code and see if it runs as per the logic. And correct it accordingly — Chetan
– Chetan, Commented May 31, 2019 at 2:06
running your test case code gives: Message: Expected: 7.0d But was: 5.0d — Amr Elgarhy
– Amr Elgarhy, Commented May 31, 2019 at 2:17

Andre Lombaard · Accepted Answer · 2019-05-31 02:25:04Z

4

You can do it with System.Linq

var saturday = new[] { 1, 2, 3, 4, 5, 7, 8, 5, 10 };
var sunday = new[] { 9, 9, 9, 8, 9, 8, 9, 9, 9, 10, 10 };

var average = saturday.Concat(sunday).DefaultIfEmpty(0).Average();

edited May 31, 2019 at 2:25

answered May 31, 2019 at 2:13

Andre Lombaard

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10 Comments

Prime Over a year ago

Can be simplified to saturday.Concat(sunday).Average()

ProgrammingLlama Over a year ago

@AlphaDelta saturday.Concat(sunday).DefaultIfEmpty(0).Average() is probably safer :)

Prime Over a year ago

@John Solid point, prevents an exception if both collections contain no items

Prime Over a year ago

Can also be extended with params and SelectMany to average an arbitrary amount of collections, see here: dotnetfiddle.net/FDnxiy

Andre Lombaard Over a year ago

Thank you. I updated the answer to include your suggestions.

|

Theodor Zoulias · Accepted Answer · 2019-05-31 03:03:43Z

2

Without Linq. Just calculate the sum and divide with the length of the combined array.

public double WeekendAverage(int[] saturday, int[] sunday)
{
    double sum = 0;
    for (int i = 0; i < saturday.Length; i++)
    {
        sum += saturday[i];
    }
    for (int i = 0; i < sunday.Length; i++)
    {
        sum += sunday[i];
    }
    return sum / (saturday.Length + sunday.Length);
}

answered May 31, 2019 at 3:03

Theodor Zoulias

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Comments

Ned · Accepted Answer · 2019-05-31 02:04:09Z

0

The length of n is 2 as an array. You want an int that stores the total of the two array lengths, not an array of integers representing the lengths of your parameters.

Change that to n = saturday.length + sunday.length and i < n in your loop.

answered May 31, 2019 at 2:04

Ned

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1 Comment

Alejandro H Over a year ago

How would I return sum?

Samuel Vidal · Accepted Answer · 2019-06-02 22:34:32Z

0

Using Linq (adapted from Theodor's answer) :

public double WeekendAverage(int[] saturday, int[] sunday)
{
    double sum = saturday.Sum() + sunday.Sum();
    return sum / (saturday.Length + sunday.Length);
}

answered Jun 2, 2019 at 22:34

Samuel Vidal

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