交换三个值（代码）：

import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int a = scan.nextInt();
int b = scan.nextInt();
int tmp = a;
a = b;
b = tmp;
System.out.println("a = " + a);
System.out.println("b = " + b);
}
}