Question

I have following code snippet in c#.

 var list = new List<string> { "a", "b", "c" };
            for (int i = 0; i < list.Count; i++)
            {
                list.Add(list[i].ToUpper());
            }

There is no compile time error in above code,but I am gettingSystem.OutOfMemoryException exception at runtime?

Answer 1

List.Count reevaluating each time you add an element.

So, you have 3 elements. After the first iteration of your for loop you will have Count == 4. So i never reach Count value (until integer overflow case, but out of memory happens earlier in your case).

You can write smth. like:

var listInUpperCase = list.Select(x => x.ToUpper())
                          .ToList();

list.AddRange(listInUpperCase);