编译错误：索引超出范围

Question

i want to write merge sort algorithm,when i debug the program and give numbers to it,it goves index out of range error,whats the problem of my code?thanks in advance.

    private void button3_Click(object sender, EventArgs e)
    {


        string[] source = textBox1.Text.Split(',');
        string[] source1 = textBox3.Text.Split(',');
        int[] nums2 = new int[source1.Length + source.Length];
        int[] nums = new int[source.Length];
        for (int i = 0; i < source.Length; i++)
        {
            nums[i] = Convert.ToInt32(source[i]);

        }
        int[] nums1 = new int[source1.Length];
        for (int j = 0; j < source1.Length; j++)
        {
            nums1[j] = Convert.ToInt32(source1[j]);
        }
        int x=0;
        int y=0;
           int z=0;

        while (x <=nums.Length && y <= nums1.Length)
        {
            if (nums[x] <= nums1[y])///it gives out of range on this line
            {
                nums2[z] = nums[x];
                x++;

            }
            else
            {
                nums2[z] = nums1[y];
                y++;
            }

            z++;
        }
        if (x > nums.Length)
        {
            while (y <= nums1.Length)
            {
                nums2[z] = nums1[y];

                z++;
                y++;
            }
            if (y > nums1.Length)
            {
                while (x <= nums.Length)
                {
                    nums2[z] = nums[x];
                    z++;
                    x++;
                }
            }
        }
        string merge = nums2[z].ToString();

       textBox4.Text = merge;

    }
}

Answer 1

First, an IndexOutOfRangeException is not a compile error, it's a runtime error.

The indexes in an array are 0-based. This means for example that an array of length 3 has indexes 0, 1 and 2, but index 3 doesn't exist and is out of range. To fix your error change <= to < on the following lines:

while (x < nums.Length && y < nums1.Length)

while (y < nums1.Length)

while (x < nums.Length)

etc...

There may be other errors in your program too - this was just the first one I saw.

Answer 2

Arrays are zero-based in C# , meaning that the first item in the array is at index 0, not index 1.

However, the Length property returns a one-based count of the number of objects in the array. So when you write x <= nums.Length , you're actually trying to access an index that it outside of the bounds of the array.

Instead, you should rewrite that section of your code as:

    while (x < nums.Length && y <  nums1.Length)
    {
        if (nums[x] <= nums1[y])
        {
            nums2[z] = nums[x];
            x++;

        }

    // etc.

Answer 3

索引从0开始，因此您应该执行以下操作：

while (x < nums.Length && y < nums1.Length)