Java Learning: Operations, operators, operands, expressions

Operation: The process of manipulating constants and variables is called arithmetic.

Number of operations: The constant or variable that participates in the operation is called the operand.

Operator: symbols that operate on constants and variables are called operators.

Arithmetic operators: + 、-、 *,/,%, + + 、--

　

/and% of the difference?
　　　　/: Division, get quotient
The same symbol is positive and the difference is negative
%: Division, get remainder
The symbol is the same as the first operand

% of applications:
x%3 equals 0 means x can be divisible by 3.
x%2 etc 1 description x is odd
Wait 0 to indicate that X is an even number

　　　

　　+ +,--operator
　　　Function: + + is added 1,--is minus 1.
Self-increment auto-decrement operator

+ +,--can be placed in front of the operand, or after the operand, at the time of operation
A: Use alone
No difference.
B: Participate in other operations using
Back: First operation, then self-increment
Front: Self-increment first, then operate

Assignment operators

　　　Basic: =
Extension: + =

The extended assignment operator implies a forced type conversion:
int a = 10;
A + = 20;
A = (data type of a) (A + 20)

comparison Operators :

　　==,!=,>,>=,<,<=

Attention:
A: The result of the comparison operator is definitely a Boolean.
B: Whether you are using "=" or "= =", you need to know for yourself.

logical operators : &, |,! , ^, &&, | |

Attention:
logical operators for connecting relationship expressions

Conclusion:
&: False if False
|: True is true
!: Change the result, take the inverse
^: same false, different true
Memory: Couple relationship (male, female, male, female)

The most commonly used logical operators;
!,&&,| |

&& and &:
The result is the same, but the && has a short-circuit effect, the left side is false and the right side is not executed.
|| and |:
As a result, but | | With short-circuit effect, left if true, the right side is not executed.

Trinocular operator

Format:?:

(comparison expression)? Expression 1: Expression 2;

Execution process:
If the condition is true, the result of the operation is an expression of 1;
If the condition is false, the result of the operation is an expression of 2;
Requirements: Get the maximum value from two data
Nested use (Gets the maximum of three numbers)

An expression: a formula that joins a constant or variable with an operator that conforms to the Java syntax can be called an expression.
The expressions of different operator joins represent different types of expression.

Java Learning: Operations, operators, operands, expressions