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List<int> myList = new List<int> { 10, 20, 30, 40, 50 };
int searchValue = 30;
int index = myList.IndexOf(searchValue);
if (index != -1)
{
Console.WriteLine($"The index of {searchValue} is: {index}");
}
else
{
Console.WriteLine($"{searchValue} was not found in the list.");
}