public class SwapVariable {public static void main(String[] args) {
// 将两个数据进行交换:method2(123,321);method5("hello","world");}public static void method1(int a, int b) {// 方法1:引入第三方变量进行互换(适用于整型/字符串型)int temp = a;a = b;b = temp;System.out.println(a + "和" + b);}public static void method2(int a, int b) {// 方法2:  System.out.printf("a = %d, b = %d\n", a, b); a = b + 0 * (b = a);  System.out.printf("a = %d, b = %d\n", a, b); }public static void method3(int a, int b) {// 方法3:System.out.printf("a = %d, b = %d\n", a, b); a = a + b; //7 b = a - b; // 7-5=2  q == p a = a - b; //7-2   System.out.printf("a = %d, b = %d\n", a, b);}public static void method4(int a, int b) {// 方法4 采用位运算符:异或   /*任何数字和自身异或,都得0;任何数字和0异或,都得自身;*/System.out.printf("a = %d, b = %d\n", a, b); a ^= b; b ^= a; a ^= b; System.out.printf("a = %d, b = %d\n", a, b);}public static void method5(String s1, String s2) {//方法5  字符串互换方法System.out.printf("s1 = %s, s2 = %s\n", s1, s2); s1 = s1 + "," + s2; s2 = s1; s1 = s1.split(",")[1]; s2 = s2.split(",")[0]; System.out.printf("s1 = %s, s2 = %s\n", s1, s2);}public static void method6(String s1, String s2) {//方法6  字符串互换方法System.out.printf("s1 = %s, s2 = %s\n", s1, s2); s1 = s2 + ((s2 = s1) == "" ? "" : ""); System.out.printf("s1 = %s, s2 = %s\n", s1, s2);}public static void printfMethod(double d,String s,int i) {//"%"表示进行格式化输出，"%"之后的内容为格式的定义。System.out.printf("%f",d);//"f"表示格式化输出浮点数。System.out.printf("%9.2f",d);//"9.2"中的9表示输出的长度，2表示小数点后的位数。System.out.printf("%+9.2f",d);//"+"表示输出的数带正负号。System.out.printf("%-9.4f",d);//"-"表示输出的数左对齐（默认为右对齐）。System.out.printf("%+-9.3f",d);//"+-"表示输出的数带正负号且左对齐。System.out.printf("%d",i);//"d"表示输出十进制整数。System.out.printf("%o",i);//"o"表示输出八进制整数。System.out.printf("%x",i);//"d"表示输出十六进制整数。System.out.printf("%#x",i);//"d"表示输出带有十六进制标志的整数。System.out.printf("%s",s);//"s"表示输出字符串。System.out.printf("输出一个浮点数：%f，一个整数：%d，一个字符串：%s",d,i,s);//可以输出多个变量，注意顺序。System.out.printf("字符串：%2$s，%1$d的十六进制数：%1$#x",i,s);//"X$"表示第几个变量。
    }}