accessArrayList.cs

var myarray = new ArrayList()
                {
                    1,
                    "Bill",
                    300,
                    4.5f
                };

//Access individual item using indexer
int firstElement = (int) myarray[0]; //returns 1
string secondElement = (string) myarray[1]; //returns "Bill"
//int secondElement = (int) myarray[1]; //Error: cannot cover string to int

//using var keyword without explicit casting
var firstElement = myarray[0]; //returns 1
var secondElement = myarray[1]; //returns "Bill"
//var fifthElement = myarray[5]; //Error: Index out of range

//update elements
myarray[0] = "Steve"; 
myarray[1] = 100;
//myarray[5] = 500; //Error: Index out of range