what outer loop and inner loop represent in bubble sort

Question

Hi i work in visual studio 2015 c# console applications .

 

I try to make bubble sort to array unsorted but i cannot do that

i search for internet about that i understand idea .

 

it is make comparison between small and largest then swap items to make in order array

 

but i cannot understand this code .

 

so that what outer loop represent and inner loop represent ? 

 

red lines for outer loop and inner loop 

/*
 * C# Program to Perform Bubble Sort
 */
using System;
class bubblesort
{
        static void Main(string[] args)
        {
            int[] a = { 30, 20, 50, 40, 10 };
            int t;
            Console.WriteLine("The Array is : ");
            for (int i = 0; i < a.Length; i++)
            {
                Console.WriteLine(a[i]);
            }
            for (int j = 0; j <= a.Length - 2; j++) outer loop
            {
                for (int i = 0; i <= a.Length - 2; i++) inner loop
                {
                    if (a[i] > a[i + 1])
                    {
                        t = a[i + 1];
                        a[i + 1] = a[i];
                        a[i] = t;
                    }
                }
            }
            Console.WriteLine("The Sorted Array :");
            foreach (int aray in a)
                Console.Write(aray + " ");
            Console.ReadLine();
        }
    }