Array.Sort(array,0,length, null) //fast
ArrayList.Sort(0,length,null) //should generate same call as first (fast
generates slow call)
These two do not call the same method
The same as:
Array.Sort(string[] items)
Array.Sort(string[] items, 0, items.length-1, Comparer.Default)
Are not the same methods
the compiler sees Array.Sort(string[]) and realises it can instead call
the generic version Array.Sort<string>(...)
The same happens when you use the comparer as null. Because null does
not have a type it can match null to IComparer<string>, thus can then
call Array.Sort<string>(string[], int, int, IComparator<string) instead
of Array.Sort(string, int, int, IComparator)
Try calling:
Array.Sort(array, 0, length, (IComparer)null)
now we're giving null an explicit type so that we for it to use the
non-generic version of Sort.
I've tried calling TrySZSort with a string array and it cannot sort it.
And Array.Sort with a string uses ArrayObjectSorter.
==========================
// check null comparer here
oTime = DateTime.Now;
Array.Sort(Items2, 0, Items.Length, (IComparer)null);
Console.WriteLine("Time to sort with Null Comparer: {0}
msec",
(DateTime.Now.Ticks - oTime.Ticks) /
TimeSpan.TicksPerMillisecond);
Time to sort with Null Comparer: 29859 msec
With both Array.Sort and Array.Sort<T> you really have to becarful which
version is being called, as even if you don't specify a generic, the
compiler can infer it from the parameters.
Thus if you had the generic method:
void Push<T>(IList<T> list, params T items[])
...
IList<int> items = new IList<int>();
Push<int>(items, 1, 2 3);
OR
Push(items, 1, 2 3)
In the second instance the compiler sees that all the parameters match
for the required type <T> thus it infers the call to Push<int>, even if
there is also a non generic method call Push as long as the signature
isn't an exact match.
To demonstrate:
static void Main(string[] args) {
Test<int>(1);
Test(1);
Test((object)1);
Test<string>("abc");
Test("abc");
Test((object)"abc");
Console.WriteLine("Press ENTER to exit");
Console.ReadLine();
}
static void Test<T>(T value) {
Console.WriteLine("Test<T>(T), value = {0}", value);
}
static void Test(object value) {
Console.WriteLine("Test(object), value = {0}", value);
}
static void Test(string value) {
Console.WriteLine("Test(string), value = {0}", value);
}
OUTPUT:
Test<T>(T), value = 1
Test<T>(T), value = 1
Test(object), value = 1
Test<T>(T), value = abc
Test(string), value = abc
Test(object), value = abc
Press ENTER to exit
efault
)