## Learn java Lesson 8: operators (1)

zyqok 2020-11-13 10:16:58
learn java lesson operators

general programme ： Returns a list of

【1】 What is an operator

So called operator , They are symbols that can participate in the operation , In our daily life , Common operators include Add 、 reduce 、 ride 、 except . So in the program , What operators are there ？ Let's take a look at . Let's create a new class Test08 【2】 Operator classification

【2.1】 Arithmetic operator

``````public static void main(String[] args) {
// Create variables x, And assign the initial value to 10
int x = 10;
// Create variables y, And assign the initial value to 5
int y = 5;
// Use operators to operate
int z = x + y;
// Print the result of the calculation
System.out.println(" The result of the calculation is ：" + z);
}``````

We copy the above code into the class , Then execute the program , You can see ,x and y The result of the addition is 15 （2） Subtraction （ - ） （3） Multiplication （ * ） （4） division ( / ) (5) Self - increment operator （++）

The self increasing operator is to add 1 Add one more time +1, The auto increment operator is added once more after two times , For example, below x ++ Yes, it will x Add yourself 1;

So this is equivalent to ： x = x + 1;

It can be interpreted as ：x Add to yourself first 1, And then assign the result to yourself , When there is an assignment operator （ namely =） when , The program computes first "=" On the right .

（6） Self reduction （ -- ）

Self decreasing and self increasing are used in the same way , opposite （7） Modular arithmetic （ % ）

Modular arithmetic , It's also called surplus budget , such as 10 / 3 The remainder is 1,13 / 3 The remainder of is also 1, This 1 It's the result of modular operations .

For example, give you a three digit integer , Let's find out what the single digits are ？ So, if we want to find this digit number ？

At this time , We can get the result by modulo , We're going to model the three digits 10.

such as 327 This three-dimensional number , He Mo 10 Namely 327 % 10, The end result is 7, That's the single digit .

Let's look at the program code as follows ： 【2.2】 Assignment operator

The assignment operation （ = ）

So called assignment budget , It is to assign a value to a variable directly , Actually x The assignment budget is also used in initialization , The initial assignment is 10. 【2.3】 Comparison operator

So called comparison operator , That is, we often use greater than in our life , Less than , be equal to , It's not equal to , Greater than or equal to , Less than or equal to these .

The result of these operators is only two results , Either it's right true, Either it's a mistake false, So we can use a boolean Type to receive their comparison results .

（1） Greater than （ > ）

notes ： There is a priority for multiple budget operators to participate in the operation , like 3 + 2 - 5 * 0 equally , Let's start with multiplication and division , Add and subtract again .

We can use parentheses , To declare the operation priority , That is, there are parentheses , Give priority to the results in parentheses .

You can see ,x > y （ namely 10 Greater than 5） The result is true, namely x > y Yes. . （2） Less than （ < ） （3） be equal to （ == ）

Two assignment operators are linked together to indicate equal to , Let's keep this in mind , Although in our daily life, it is often written as 1 individual =, But in the program ,1 individual = It's the assignment symbol . In order to distinguish between , Is designed to be 2 individual =.

The arrow code below is understood as ： take x and y Is it equal or not , The result of the comparison is assigned as z,x by 10,y by 5, Obviously, the two are not equal , So the result of the assignment is false; (4) Greater than or equal to （ >= ） (5) Less than or equal to ( <= ) (6) It's not equal to （ != ） 