java 判断两个数是否异号

java 整型int占4个字节32位，两个数异或后移动31位判断结果，如果是1则异号，如果是0则同号

 1 public class ShowEnviromentViarible { 2  3     public static void main(String[] args) { 4         int num1 = 1; 5         int num2 = -1; 6         System.out.println("num1 = " + num1); 7         System.out.println("num2 = " + num2); 8         System.out.println((num1 ^ num2) >>> 31);    //无符号移动31位，最左边补0 9         num1 = 1;10         num2 = 1;11         System.out.println("num1 = " + num1);12         System.out.println("num2 = " + num2);13         System.out.println((num1 ^ num2) >>> 31);14         num1 = -1;15         num2 = -1;16         System.out.println("num1 = " + num1);17         System.out.println("num2 = " + num2);18         System.out.println((num1 ^ num2) >>> 31);19     }20 21 }

output:

num1 = 1num2 = -11num1 = 1num2 = 10num1 = -1num2 = -10