Understanding IndexOutOfRangeException Exception in C#

It occurs when Index is outside the bounds of the array.

Let us see an example. We have declare an array with 5 elements and set the size as 5.

int[] arr = new int[5];
arr[0] = 10;
arr[1] = 20;
arr[2] = 30;
arr[3] = 40;
arr[4] = 50;

Now, we try to add the value of an element that extends the size of our array i.e.

arr[5] = 60;

Above, we are trying to add element at 6^th position.

Example

 Live Demo

using System;
using System.IO;
using System.Collections.Generic;
namespace Demo {
   class Program {
      static void Main(string[] args) {
         int[] arr = new int[5];
         arr[0] = 10;
         arr[1] = 20;
         arr[2] = 30;
         arr[3] = 40;
         arr[4] = 50;
         arr[5] = 60; // this shows an error
      }
   }
}

Output

The following is the output. It shows the following error −

Unhandled Exception:
System.IndexOutOfRangeException: Index was outside the bounds of the array.