while
int n = 1;
      while (n < 6)
      {
         Console.WriteLine("Current value of n is {0}", n);
         n++;
      }
do
      int x;
      int y = 0;
      do
      {
         x = y++;
         Console.WriteLine(x);
      }
      while(y < 5);
for
for (int i = 1; i <= 5; i++)
         Console.WriteLine(i);

for each
public static void Main()
   {
      int odd = 0, even = 0;
      int[] arr = new int [] {0,1,2,5,7,8,11};
      foreach (int i in arr)
      {
         if (i%2 == 0) 
            even++;     
         else
            odd++;        
      }
      Console.WriteLine("Found {0} Odd Numbers, and {1} Even Numbers.",
                        odd, even) ;
   }