Bitwise operations in Java--java Programming thought notes

Welcome reprint, Reproduced Please be sure to indicate the source: http://blog.csdn.net/alading2009/article/details/40450421

There are four bitwise operators in Java :& (Bitwise AND), | (bitwise OR), ^ (bitwise XOR), ~ (bitwise non).

1, first look at the bitwise AND (&)

public class Main {public    static void Main (string[] args) {        //bitwise with, 21 to 1, 0 to 0        System.out.println ( Integer.tobinarystring ());        System.out.println (Integer.tobinarystring (one));        System.out.println (integer.tobinarystring (13&11));}            }

The result is:

110110111001

From the results can be clearly seen, with the rule is: two-bit phase, if one is 0, then the result is 0, otherwise 1.

2, then the bitwise OR (|)

<span style= "FONT-SIZE:18PX;" >public class Main {public    static void Main (string[] args) {        //bitwise OR, 20 to 0, 1 to 1        System.out.println ( Integer.tobinarystring ());        System.out.println (Integer.tobinarystring (one));        System.out.println (integer.tobinarystring (13|11));}    } </span>

The result is:

110110111111

So you get a bitwise OR result.

3. Next is the bitwise XOR or

public class Main {public    static void Main (string[] args) {        //Bitwise XOR: Two-bit different 1, two-bit same 0        System.out.println ( Integer.tobinarystring ());        System.out.println (Integer.tobinarystring (one));        System.out.println ("0" +integer.tobinarystring (13^11));}    }

The result is:

110110110110

Different 1, same 0.

Bitwise XOR or has an interesting usage, it can exchange two number of values without a third-party variable, as follows

public class Main {public    static void Main (string[] args) {        //Use bitwise XOR or Exchange two-number value        int temp1=10;        int temp2=114;        System.out.println ("Before Exchange: Temp1:" +TEMP1);        System.out.println ("Before Exchange: Temp2:" +TEMP2);        TEMP1^=TEMP2;        TEMP2^=TEMP1;        TEMP1^=TEMP2;        SYSTEM.OUT.PRINTLN ("After Exchange: Temp1:" +TEMP1);        SYSTEM.OUT.PRINTLN ("After Exchange: Temp2:" +TEMP2);}    }

The result is:

Before: Temp1:10 swap: temp2:114 after Exchange: temp1:114 after Exchange: Temp2:10

There is a basis for this, so to see,

The first step: TEMP1^=TEMP2, that is, TEMP1=TEMP1^TEMP2

Step Two: temp2=temp2^temp1=temp2^ (TEMP1^TEMP2), XOR or satisfy the commutative law, after the parentheses are finally obtained TEMP2=TEMP1

Step three: Temp1=temp1^temp2= (TEMP1^TEMP2) ^TEMP2=TEMP1^TEMP2^TEMP1=TEMP2

After these three steps, the values of the two variables are exchanged smoothly.

This method tells us that the swap function can be implemented in C + +

    int swap (int &a, int &b) {        a^=b;        B^=a;        a^=b;    }

The use of the reference, of course, you can also use a pointer to the way to achieve

4, the last is the bitwise NON (~)

public class Main {public    static void Main (string[] args) {        //bitwise NON: Bitwise de-        System.out.println (" 0000000000000000000000000000 "+integer.tobinarystring ());        System.out.println (integer.tobinarystring (~13));}    }

The result is:

0000000000000000000000000000110111111111111111111111111111110010

Welcome reprint, Reproduced Please be sure to indicate the source: http://blog.csdn.net/alading2009/article/details/40450421

Bitwise operations in Java--java Programming thought notes