Java五种运算符

桃扇骨 2022-05-16 04:37 151阅读 0赞

## 五种运算符 ##

> 算数运算符

1.  \+；-；\*；/;%  
    进行除法运算时应注意口诀（自己瞎想的，不喜勿喷）  
    整数相除取商数（/）  
    整数相除取余数（%）  
    整数相除只得整  
    要得小数必浮点

package Test2;
    
    public class OperatorDemo {
        public static void main(String[] args) {
            int a = 3;
            int b = 4;
    
            System.out.println(a+b);
            System.out.println(a-b);
            System.out.println(a*b);
    
            //整数相除取商数
            System.out.println(a/b);
    
            //整数相除取余数
            System.out.println(a%b);
    
            //整数相除只得整,要得小数必浮点
            System.out.println(3.0/b);
            System.out.println(a/4.0);
            System.out.println(3.0/4.0);
    
        }
    }

1.  \++；–  
    \++在前，先自加一再用  
    \++在后，先用再自加一  
    –在前，先自减一再用  
    –在后，先用再自减一

package Test2;
    
    public class OperatorDome2 {
        public static void main(String[] args) {
            int a = 8;
            int b = ++a;//b=a+1
            System.out.println("b: "+b);
    
            int d = 8;
            int c = d++;//c=d;d=d+1
            System.out.println("c: "+c);
    
        }
    }

得到b=9;c=8

> 赋值运算符

1.  =；+=；-=；\*=；/=

package Test2;
    
    public class OperatorDemo3 {
        public static void main(String[] args) {
            int a = 10;
    
            a += 5;//a=a+5
            System.out.println("a:"+a);
    
            a -= 5;//a=a-5
            System.out.println("a:"+a);
    
            a *= 5;//a=a*5
            System.out.println("a:"+a);
    
            a /=5;//a=a/5
            System.out.println("a:"+a);
    
            //隐含了强制转换，“=”右边默认是int类型
            //相当于 b = (b的类型)(b+1)
            byte b = 1;
            b += 1;
            System.out.println("b:"+b);
        }
    }

注意：赋值运算符实际上隐含了强制转换

> 关系运算符

1.  ==；！=；>;<;>=;<=（其结果都是boolean类型）

package Test2;
    
    public class OperatorDemo4 {
        public static void main(String[] args) {
            int a = 3;
            int b = 4;
            int c = 3;
    
            System.out.println(a==b);
            System.out.println(a==c);
            System.out.println("............");
    
            System.out.println(a!=b);
            System.out.println(a!=c);
            System.out.println("............");
    
            System.out.println(a>b);
            System.out.println(a>c);
            System.out.println("............");
    
            System.out.println(a>=b);
            System.out.println(a>=c);
            System.out.println("............");
    
            System.out.println(a<b);
            System.out.println(a<c);
            System.out.println("............");
    
            System.out.println(a<=b);
            System.out.println(a<=c);
            System.out.println("............");
        }
    }

> 逻辑运算符

1.  &；|；^;！  
    有错（flase）则错（flase）【&】  
    有对（true）则对（true）【|】  
    相同则错（flase）【^】  
    不同则对（true）【^】  
    对就是错（flase）【！】  
    错（flase）就是对（true）【！】

package Test2;
    
    public class OperatorDemo5 {
        public static void main(String[] args) {
            int a = 3;
            int b = 4;
            int c = 5;
    
            System.out.println((a>b)&(a>c));//flase & flase
            System.out.println((a<b)&(a>c));//true & flase
            System.out.println((a>b)&(a<c));//flase & true      
            System.out.println((a<b)&(a<c));//true & true
            System.out.println("............");
    
            System.out.println((a>b)|(a>c));//flase | flase
            System.out.println((a<b)|(a>c));//true | flase
            System.out.println((a>b)|(a<c));//flase | true      
            System.out.println((a<b)|(a<c));//true | true
            System.out.println("............");
    
            System.out.println((a>b)^(a>c));//flase ^ flase
            System.out.println((a<b)^(a>c));//true ^ flase
            System.out.println((a>b)^(a<c));//flase ^ true      
            System.out.println((a<b)^(a<c));//true ^ true
            System.out.println("............");
    
            System.out.println(!(a>b));//!flase 
            System.out.println(!!(a>b));//!!flase
            System.out.println("............");
        }
    }

1.  &&；||  
    &&和&  
    相同点：结果一样  
    不同点：&&有短路效果，若左边为flase，则右边不执行  
    &无论左边是true或flase，右边都会执行
    
    ||和|  
    相同点：结果一样  
    不同点：||有短路效果，若左边为true，则右边不执行  
    |无论左边是true或flase，右边都会执行

package Test2;
    
    public class OperatorDemo6 {
        public static void main(String[] args) {
            int a = 3;
            int b = 4;
            int c = 5;
    
            System.out.println((a>b)&&(a>c));//flase && flase
            System.out.println((a<b)&&(a>c));//true && flase
            System.out.println((a>b)&&(a<c));//flase && true        
            System.out.println((a<b)&&(a<c));//true && true
            System.out.println("............");
    
            System.out.println((a>b)||(a>c));//flase || flase
            System.out.println((a<b)||(a>c));//true || flase
            System.out.println((a>b)||(a<c));//flase || true        
            System.out.println((a<b)||(a<c));//true || true
            System.out.println("............");
    
            //&&与&的区别
            int x = 6;
            int y = 7;
            System.out.println((x++>6)&(y++>7));
            System.out.println("x:"+x);
            System.out.println("y:"+y);
    
            int x1 = 6;
            int y1 = 7;
            System.out.println((x1++>6)&&(y1++>7));
            System.out.println("x1:"+x1);
            System.out.println("y1:"+y1);
            System.out.println("............");
    
            //||与|的区别
            int x2 = 6;
            int y2 = 7;
            System.out.println((x2++>=6)|(y2++>=7));
            System.out.println("x2:"+x2);
            System.out.println("y2:"+y2);
    
            int x3 = 6;
            int y3 = 7;
            System.out.println((x3++>=6)||(y3++>=7));
            System.out.println("x3:"+x3);
            System.out.println("y3:"+y3);
            System.out.println("............");
    
    
    
        }
    }

> 三元运算符

1.  关系表达式？表达式1：表达式2  
    计算关系表达式的值看是true还是flase;  
    若是true则表达式1就是结果  
    若是flasez则表达式2就是结果

package Test2;
    
    public class OperatorDemo7 {
        public static void main(String[] args) {
            int a = 3;
            int b = 4;
    
            int c = (a>b)?a:b;
            System.out.println("c:"+c);
        }
    }