using System;
class MainClass {
public static void Main() {
string str = "abcdefghijk";
int idx;
char[] chrs = { 'a', 'b', 'c' };
idx = str.IndexOfAny(chrs);
Console.WriteLine("Index of first 'a', 'b', or 'c': " + idx);
}
}
Index of first 'a', 'b', or 'c': 0