What is the difference between &, |, && and || in Java?

This article will introduce to you the differences between &, |, &&, and || in Java. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to everyone.

In Java, & is called bitwise AND, && is called short-circuit AND. The difference between them is:

& is a bitwise operator It is also a logical operator. Both sides of & can be int or boolean expressions. When both sides of & are ints, the numbers on both sides of the operator must be converted into binary numbers before operation, and the short-circuit with ( &&) must be Boolean expressions on both sides. For example: What is the value of

12&5? Answer: 12 converted to binary number is 1100 (the first four digits are omitted), 5 converted to binary number is 0101, then the result after operation is 0100 or 4. This is when both sides are numerical values;

If int i = 2, j = 4; then the result of (i=2)&(j =4) is false. The process is as follows: first determine whether i=2 is true. Of course it is not true here (3 == 2) , but the program will continue to judge whether the next expression is true, j = 4, this expression is true, but the & operator requires the values ​​on both sides of the operator to be true for the result to be true, so (i=2 )&(j =4) results in false Note: The condition for

& to be true is that both expressions on both sides are true, but even if we judge that the value of the expression on the left is false, the program will still To continue execution to determine whether the expression value on the right is true or false

If int i = 2, j = 4; then the result of (i=2)&&(j =4) is false, and the process is basically The above is the same as the above, but if the value of the expression on the left is false, the program will not continue to judge whether the expression on the right is true or false. Short circuit and middle, this is probably what the word short circuit means

The difference between '|' and '||' in Java

int i=0;
if(3>2 || (i++)>1) i=i+1;
System.out.println(i);

This program will print out 1 instead of 2.

Because in the conditional judgment of if, the program first judges whether the first expression 3>2 is true, and the result 3>2 is true, then according to logic, no matter the following expression (i)> Whether ;1 is true, the entire OR expression must be true, so the program will not execute the judgment of the next expression, that is, (i)>1, so i does not increase by 1 here. Then the program executes until i=i 1, so i becomes 1. Finally print out 1.

int i=0;
if(3>2 | (i++)>1) i=i+1;
System.out.println(i);

If you write it like this, it will print out 2, because no matter whether the first condition 3>2 is true or not, the program will execute the judgment of the second conditional expression, so i This auto-increment will be executed, plus i=i 1 in if, so eventually i=2.

Some people are used to calling || a short-circuit or, and && a short-circuit and. The difference between && and & is similar to the difference between || and |. For &&, if the previous conditional expression is already false, the entire conditional expression must be false, and the subsequent conditional expression will not be judged.

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