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c#arraysinsertionindexoutofrangeexception

Inserting element into array using c#

        int[] arr = {4,3,6,7,9,12};

        int n = arr.Length;
        n = n + 1;

        for (int i =n;i>2;i--) { 
        arr[i-1] = arr[i-2];

        }

        arr[0] = 4;

The above code returning

indexOutOfRangeexception.

Solution 
  • int n = arr.Length //n=6
n=n+1 //n=7
for(int i=n;i>2;i--){ //i=7
  arr[i-1] //arr[6]

    While clearly the last element is arr[5]. In C# arrays are of constant length, you can't change them, the only way to do that is to create a new array, or a better solution would be using List<>