Java中移位运算

太过爱你忘了你带给我的痛 2022-05-16 13:17 127阅读 0赞

# java中有三种移位运算符 #

*  `<<`:左移运算符，num << 1,相当于num乘以2
 *  `>>`:右移运算符，num >> 1,相当于num除以2
 *  `>>>`:无符号右移，忽略符号位，空位都以0补齐

## 正数时： ##

public class ShiftTest { 
    
        @Test
        public void shiftTest() {
            int num = 84;
            System.out.printf("num 二进制:{%s}\r\n", Integer.toBinaryString(num));
            System.out.printf("num >>> 2 = {%s} = {%d}\r\n", int2ByteStr(num >>> 2), (num >>> 2));
            System.out.printf("num >> 2 = {%s} = {%d}\r\n", int2ByteStr(num >> 2), (num >> 2));
            System.out.printf("num << 2 = {%s} = {%d}\r\n", int2ByteStr(num << 2), (num << 2));
        }
    
        /** * @param num */
        private String int2ByteStr(int num) {
            return Integer.toBinaryString(num);
        }
    
    }

## 结果图： ##

![整数时：][WEBRESOURCEf61d6e01656c88c1e668aa8c0ca9dedc]

## 负数时： ##

@Test
        public void shiftTest() {
            int num = -84;
            System.out.printf("num 二进制:{%s}\r\n", Integer.toBinaryString(num));
            System.out.printf("num >>> 2 = {%s} = {%d}\r\n", int2ByteStr(num >>> 2), (num >>> 2));
            System.out.printf("num >> 2 = {%s} = {%d}\r\n", int2ByteStr(num >> 2), (num >> 2));
            System.out.printf("num << 2 = {%s} = {%d}\r\n", int2ByteStr(num << 2), (num << 2));
        }
    
        /** * @param num */
        private String int2ByteStr(int num) {
            return Integer.toBinaryString(num);
        }

结果图：

## ![负数][WEBRESOURCE19426ac7cfbdc5b0e6a45cee6ef2c130] ##

#### `负数时符号位需要注意` ####

[WEBRESOURCEf61d6e01656c88c1e668aa8c0ca9dedc]: https://note.youdao.com/yws/res/29/WEBRESOURCEf61d6e01656c88c1e668aa8c0ca9dedc
[WEBRESOURCE19426ac7cfbdc5b0e6a45cee6ef2c130]: https://note.youdao.com/yws/res/46/WEBRESOURCE19426ac7cfbdc5b0e6a45cee6ef2c130