运算符
java语言支持如下运算符：
- 算术运算符:+，-，*，l， %，++，
- 赋值运算符=
- 关系运算符:>，<，>=，<=，==，!= instanceof
- 逻辑运算符: &&，|，!
- 位运算符:&，|，^, ~，>>，<<，>>>(了解!! ! )
- 条件运算符?∶
- 扩展赋值运算符:+=，-=，*=，/=
算术运算符
package opertaor;
public class Demo01 {
public static void main(String[] args) {
//二元运算符
//Ctrl+D:复制当前行到下一行
int a =10;
int b =20;
int c =25;
int d =25;
System.out.println(a+b);
System.out.println(a-b);
System.out.println(a*b);
System.out.println(a/(double)b );//强制类型转换 0.5
}
}
//运行结果
30
-10
200
0.5
Process finished with exit code 0
package opertaor;
public class Demo04 {
public static void main(String[] args) {
//自增自减
//++ -- 自增，自减 一元运算符
int a =3;
int b =a++; //执行完这行代码后，先给b赋值，再自增
//a++ a=a+1
System.out.println(a);//4
int c=++a; //执行完这行代码前，先自增，再给b赋值
System.out.println(a);//5
System.out.println(b);//3
System.out.println(c);//5
//幂运算2^3 2*2*2=8 很多运算，我们会使用一些工具类来操作！
double pow = Math.pow(3, 2);
System.out.println(pow);
}
}
//运行结果
4
5
3
5
9.0
Process finished with exit code 0
赋值运算符
package opertaor;
public class Demo02 {
public static void main(String[] args) {
long a=12312321341432L;
int b=123;
short c=10;
byte d=8;
System.out.println(a+b+c+d); //Long
System.out.println(b+c+d); //Int
System.out.println(c+d); //Int
}
}
//运行结果
12312321341573
141
18
Process finished with exit code 0
关系运算符
package opertaor;
public class Demo03 {
public static void main(String[] args) {
//关系运算符返回的结果：正确，错误 布尔值
int a=10;
int b=20;
int c=22;
//取余，模运算
System.out.println(c%a); //c/a 22/10=2.......1
System.out.println(a>b);
System.out.println(a<b);
System.out.println(a==b);
System.out.println(a!=b);
}
}
//运行结果
2
false
true
false
true
Process finished with exit code 0
package opertaor;
//逻辑运算
public class Demo05 {
public static void main(String[] args) {
//与（and） 或（or） 非（取反）
boolean a = true;
boolean b = false;
System.out.println("a&&b:"+(b&&a)); //逻辑与运算：两个变量都为真，结果才为true
System.out.println("a||b:"+(a||b)); //逻辑或运算：两个变量有一个为真，则结果才为true
System.out.println("!(a&&b)："+!(a&&b)); //如果是真，则变为假。
//短路运算
int c = 5;
boolean d=(c<4)&&(c++<4);
}
}
//运行结果
a&&b:false
a||b:true
!(a&&b)：true
Process finished with exit code 0
位运算符
package opertaor;
public class Demo06 {
public static void main(String[] args) {
/*
A = 0011 1100
B = 0000 1101
------------------------------
A&B = 0000 1100
A|B = 0011 1101
A^B = 0011 0001
~B = 1111 0010
2*8 = 16 2*2*2*2
效率极高
<< 左移 *2
>> 右移 /2
0000 0000 0
0000 0001 1
0000 0010 2
0000 0100 4
0000 1000 8
0001 0000 16
*/
System.out.println(2<<3);
}
}
//运行结果
16
Process finished with exit code 0
条件运算符
package opertaor;
public class Demo07 {
public static void main(String[] args) {
int a = 10;
int b = 20;
a+=b; //a=a+b
System.out.println(a);
a-=b; //a=a-b
System.out.println(a);
//字符串拼接 + ， String
System.out.println(""+a+b);
System.out.println(a+b+"");
}
}
//运行结果
30
10
1020
30
Process finished with exit code 0
三元运算符
package opertaor;
//三元运算符
public class Demo08 {
public static void main(String[] args) {
//x? y : z
//如果x==true,则结果为y,否则结果为z
int score = 50;
String type = score < 60?"不及格":"及格";
//if
System.out.println(type);
}
}
不及格
Process finished with exit code 0