using System; 

public class array{ 

    public static void arrangeOddAndEven(int[] arr, int n) 

    { 

     int oddInd = 1; 

     int evenInd = 0; 

    while (true) 

    { 

        while (evenInd < n && arr[evenInd] % 2 == 0) 

            evenInd += 2; 

        while (oddInd < n && arr[oddInd] % 2 == 1) 

            oddInd += 2; 

        if (evenInd < n && oddInd < n) 

            { 

                int temp = arr[evenInd]; 

                arr[evenInd] = arr[oddInd]; 

                arr[oddInd] = temp; 

            } 

        else

            break; 

    } 

    } 

    public static void printArray(int[] arr, int n) 

    { 

        for (int i = 0; i < n; i++) 

            Console.Write(arr[i] + " "); 

    } 

    public static void Main() 

    { 

        int[] arr = { 3, 2, 9, 4, 15, 8 }; 

        int n = 6; 

        Console.Write("Original Array: "); 

        printArray(arr, n); 

        arrangeOddAndEven(arr, n); 

        Console.Write("\nModified Array: "); 

        printArray(arr, n); 

    } 

}