Counter in foreach loop in C# -

working of foreach: know,

foreach loop iterates through collection or array 1 one, starting 0 index till last item of collection.

so, if have n items in array.

foreach (var item in arr) {  }   

then, in, 1st iteration, item=arr[0];
then, in 2nd, item=arr[1];
.
.
.
in last (nth), item=arr[n-1];

conclusion: working seems @ each iteration knows value taken array or knows index of item taken array.

now question: how can index of item without using new variable?

foreach (string item in mylist) {    if (item == "myitem")    {        // index of item        break;    } } 

it depends mean "it". iterator knows index it's reached, yes - in case of list<t> or array. there's no general index within ienumerator<t>. whether it's iterating on indexed collection or not implementation. plenty of collections don't support direct indexing.

(in fact, foreach doesn't use iterator @ all. if compile-time type of collection array, compiler iterate on using array[0], array[1] etc. likewise collection can have method called getenumerator() returns type appropriate members, without implementation of ienumerable/ienumerator in sight.)

options maintaining index:

• use for loop
• use separate variable

• use projection projects each item index/value pair, e.g.

   foreach (var x in list.select((value, index) => new { value, index }))  {      // use x.value , x.index in here  } 

• use smartenumerable class little bit previous option

all first of these options work whether or not collection naturally indexed.