交换两个数的方法

//交换两个数：借助中间变量
public static void swap1 (int a, int b) {
System.err.println("交换前: a=" + a + ", b=" + b);
int temp;
temp = a;
a = b;
b = temp;
System.err.println("交换后: a=" + a + ", b=" + b);
}
//交换两个数：
public static void swap2 (int a, int b) {
System.err.println("交换前: a=" + a + ", b=" + b);
a = a + b;
b = a - b;
a = a - b;
System.err.println("交换后: a=" + a + ", b=" + b);
}
//交换两个数：异或
public static void swap3 (int a, int b) {
System.err.println("交换前: a=" + a + ", b=" + b);
a = a^b;
b = a^b;
a = a^b;
System.err.println("交换后: a=" + a + ", b=" + b);
}