Introduction to Java Basics essay (3) version javase

The previous section notes some of the operators ' considerations, and the beginning of this section is still an elaboration of some of the operators ' points of attention!

Comparison operators need to be aware of instanceof, except for >, >=, <, <=, = =,! =, to check if the object is a class, for example: "Hello" instanceof String, which returns the result bit true.

1. Logical operators

& (and) operation characteristics: The operation of the two sides as long as there is a false, the result is definitely false, only the two sides are true, the result is true;

| (or) operation characteristics: As long as there is a true on both sides of the operation, the result is definitely true, only both sides are false, the result is false;

^ (XOR) Operation characteristics: The results of both sides of the operation if the same, the result is false, the results are different on both sides, the result is true;

！ (non) Operational characteristics: Judging the other side of things;

&& (short-circuit double and) operation characteristics: and the & operation is basically the same, just && when the left is false, the right does not participate in the operation, and & both sides have to operate;

|| (short-circuit dual or) of the operation characteristics: and | Operation basically consistent, just | | When the left is true, the right side does not participate in the operation, but | Both sides have to be calculated;

2. Bitwise operators

& (with bitwise operators): The operations feature is the same as the & of the logical operators, except for binary bitwise operations, such as:6&3=2; (binary principle: 110&011=010), any number with a bit of 1 fetch & The operation is the original number (the function takes some significant number of digits);

| (or operator): the & of the arithmetic characteristic or logical operator is just the bit operation for the binary, for example: 6|3=7; (binary principle: 110|011=111);

^ (XOR operator): The arithmetic characteristic is the same as the ^ of the logical operator, but here is the bitwise operation for the binary, for example: 6^3^3 = 6, note: When a number is different or the operation is the same number two times, the result is the number itself (the effect of the encryption)

~ (Inverse code operator): The operation characteristics are the same as in the operator's logical operators!

<< (left shift operator): The number of left shifts is actually the number of times the data is multiplied by 2. You can complete the power operation of 2!

>> (right shift operator): The right shift is the number of times the data is divided by 2 power. For high-level appearance of the vacancy, the original high is what to fill this vacancy!

>>> (unsigned right-shift operator): When the data is moved to the right, the upper position appears empty, regardless of the original high, the empty space is 0 complement.

Practice:

1.//the most efficient way to figure out 2 times 8 equals a few? Answer: System.out.println (2<<3);

2. Swap the values of two integer variables?

Answer:

When developing, use the form of third-party variables because of the strong reading.
int C;
c = A;
A = b;
b = C;

Do not use this method, if the value of the two integer is too large, it will exceed the int range, will be cast. Data will
Change.

A = a + B; A = 3 + 5;a = 8;
b = a A; 3+5-5 = 3;b = 3;
A = a-B; 3+5-3 = 5;a = 5;

Use it during the interview.
A = a ^ b; A = 3 ^ 5;
b = a ^ b; b = (3^5) ^5; b = 3;
A = a ^ b; A = (3^5) ^3; A = 5;

Introduction to Java Basics essay (3) version javase