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淺談java中的移動位運(yùn)算：,>>>

更新時間：2019年03月07日 16:17:09 作者：weixin_34414196

這篇文章主要介紹了java中的移動位運(yùn)算：,>>>文中通過示例代碼介紹的非常詳細(xì)，對大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧

1. 概念

<< 左移運(yùn)算符，左移是在后面補(bǔ)0， num << 1,相當(dāng)于num乘以2
>> 右移運(yùn)算符, 右移是在前面補(bǔ)1或0，num >> 1, 相當(dāng)于num除以2
>>> 無符號右移，是在前面補(bǔ)0，忽略符號位，空位都以0補(bǔ)齊
另外，不論是左右還是右移32位，相當(dāng)于不移動，還是原值。

實(shí)際上在java虛擬機(jī)執(zhí)行這句代碼的時候如下這樣執(zhí)行的：
5>>(n%32)--->結(jié)果
你這里n=32 ；所以5>>32即是 5>>(32%32)-->5>>0 的結(jié)果；

2. 測試代碼

public class Test{
 public Test(){
 System.out.println("=============算術(shù)右移 >> ===========");
 int i=0xC0000000;
 System.out.println("移位前：i= "+i+" = "+Integer.toBinaryString(i)+"(B)");
 i=i>>28;
 System.out.println("移位后：i= "+i+" = "+Integer.toBinaryString(i)+"(B)");
 
 System.out.println("---------------------------------");
 
 int j=0x0C000000;
 System.out.println("移位前：j= "+j+" = "+Integer.toBinaryString(j)+"(B)");
 j=j>>24;
 System.out.println("移位后：j= "+j+" = "+Integer.toBinaryString(j)+"(B)");
 
 System.out.println("\n");
 System.out.println("==============邏輯右移 >>> =============");
 int m=0xC0000000;
 System.out.println("移位前：m= "+m+" = "+Integer.toBinaryString(m)+"(B)");
 m=m >>> 28;
 System.out.println("移位后：m= "+m+" = "+Integer.toBinaryString(m)+"(B)");
 
 System.out.println("---------------------------------");
 
 int n=0x0C000000;
 System.out.println("移位前：n= "+n+" = "+Integer.toBinaryString(n)+"(B)");
 n=n>>24;
 System.out.println("移位后：n= "+n+" = "+Integer.toBinaryString(n)+"(B)");
 
 System.out.println("\n");
 System.out.println("==============移位符號的取模===============");
 int a=0xCC000000;
 System.out.println("移位前：a= "+a+" = "+Integer.toBinaryString(a)+"(B)");
 System.out.println("算術(shù)右移32：a="+(a>>32)+" = "+Integer.toBinaryString(a>>32)+"(B)");
 System.out.println("邏輯右移32：a="+(a>>>32)+" = "+Integer.toBinaryString(a>>>32)+"(B)");
 
 System.out.println("算術(shù)右移64：a="+(a>>64)+" = "+Integer.toBinaryString(a>>64)+"(B)");
 System.out.println("邏輯右移64：a="+(a>>>64)+" = "+Integer.toBinaryString(a>>>64)+"(B)");
 
 }
 
 public static void main(String[] args){
 new Test();
 }
 
}

運(yùn)行結(jié)果：

=============算術(shù)右移 >> ===========
移位前：i= -1073741824 = 11000000000000000000000000000000(B)
移位后：i= -4 = 11111111111111111111111111111100(B)

移位前：j= 201326592 = 1100000000000000000000000000(B)
移位后：j= 12 = 1100(B)

==============邏輯右移 >>> =============
移位前：m= -1073741824 = 11000000000000000000000000000000(B)
移位后：m= 12 = 1100(B)

移位前：n= 201326592 = 1100000000000000000000000000(B)
移位后：n= 12 = 1100(B)

==============移位符號的取模===============
移位前：a= -872415232 = 11001100000000000000000000000000(B)
算術(shù)右移32：a=-872415232 = 11001100000000000000000000000000(B)
邏輯右移32：a=-872415232 = 11001100000000000000000000000000(B)
算術(shù)右移64：a=-872415232 = 11001100000000000000000000000000(B)
邏輯右移64：a=-872415232 = 11001100000000000000000000000000(B)