数组索引超出范围异常C＃

Question

I'm trying to find the closest number in an array when compared to the array's average. The array will be determined in the main program. Here's the current code:

public static void Main()
{
    double[] numbers = { 1, 2, 3, 2, 5 };    
    double m1 = Miidi(numbers);         
    double m2 = Miidi(new double[] { 1 });  
    double m3 = Miidi(new double[] { 3, 3 });
    double m4 = Miidi(new double[] { });
    Console.WriteLine(m1);
    Console.WriteLine(m2);
    Console.WriteLine(m3);
    Console.WriteLine(m4);
}

public static double Miidi(double[] numbers)
{
    double average = 0;
    average = numbers.Average();

    double nearest = FindNearest(numbers, average);
    return nearest;
}

public static double FindNearest(double[] t, double avg)
{
    double searchValue = avg;
    double currentNearest = t[0];
    double currentDiff = currentNearest - searchValue;

    for (int i = 0; i < t.Length; i++)
    {
        double diff = t[i] - avg;
        if (diff < currentDiff)
        {
            currentDiff = diff;
            currentNearest = t[i];
        }
    }
    return currentNearest;
}

}

I'm getting an array index out of range exception. I tried the methods you guys provided and changed the <= to < in the loop, but I'm still getting the exception. I provided the main program for clarification.

Answer 1

Additional to my comment:

An array/collection starts always at 0.

eg

t[0] = 1;
t[1] = 2;
t[2] = 3;
t[3] = 4;

If you loop t like this:

for(int i = 0; i <= t.Length; i++)

then i will count the following:

0
1
2
3
4

because t.Length = 4 and you say i less than equal 4 .

But since an array starts at 0, i may not be greater than 3, otherwise it will throw an IndexOutOfRangeExcepiton .

If you change your loop to

for (int i = 0; i < t.Length; i++)

it will finish without any exception, because i wont be greater than 3 now.

UPDATE:

Additional to your comments:

You pass an empty array to your method Miidi() . Just check if there are any items in the array:

public static double Miidi(double[] numbers)
{
    if (numbers != null && numbers.Length > 0)
    {
        double average = 0;
        average = numbers.Average();

        double nearest = FindNearest(numbers, average);
        return nearest;
    }

    return 0;
}

Answer 2

Change your for loop

for (int i = 0; i <= t.Length; i++)

as

for (int i = 0; i <= t.Length - 1; i++)

because an Array starts at 0