import java.util.*;

public class App {
	public static void main(String [] args) {
		int a = 10, b = 20;
		System.out.println("a: " + a + " b: " + b);
		swap(a, b);
		System.out.println("After swap(a, b)... a: " + a + " b: " + b);
		System.out.println();

		swap(3, 4);
		System.out.println("After swap(3, 4)... 3: " + 3 + " 4: " + 4);
		System.out.println();

		int [] arr = {0, 10, 20, 30, 40, 50};
		System.out.print("arr: " );
		print(arr);
		System.out.println();
		swap(arr, 2, 4);
		System.out.println("After swap(arr, 2, 4)... arr: ");
		print(arr);
		System.out.println();
	}

	static void swap(int x, int y) {
		int t = x;
		x = y;
		y = t;
	}

	static void swap(int [] arr, int index1, int index2) {
		int t = arr[index1];;
		arr[index1] = arr[index2];
		arr[index2] = t;
	}

	static void print(int [] arr) {
		for (int e : arr)
			System.out.print(e + " ");
	}
}