运算符

一元运算符

• ++在左边 先++后赋值 ++在右边 先赋值后再++
• --在左边 先-- 在赋值 --在右边 先赋值后--

    public static void main(String[] args) {
        System.out.println("==一元运算符==");
        int a = 3;
        int b = a++; //a=3 赋值给b b=3 a=a+1 4
        int c = ++a; //a = 5 赋值给c c=5

        System.out.println(a); //5

        System.out.println(b); //3

        System.out.println(c); //5
    }
}

赋值运算符

int x = 10;
int y = 20;

x+=y;
//x = x+y
System.out.println(x); //30

关系运算符

System.out.println(x == y);
System.out.println(x != y);
System.out.println(x >= y);
System.out.println(x <= y);
System.out.println(y > x);

逻辑运算符

• && 逻辑与 两个都为真就是真 and
• || 逻辑或 其中一个为真就是真 or
• ! 取反

System.out.println("a1 && a2 = "  + (a1 && a2)); //false
System.out.println("a1 || a2 = " + (a1 || a2)); //true
System.out.println("a1 ! a2 = " + !(a1 ||a2)); //false

三元运算符

int age = 18;
int age1 = 20;

System.out.println(age > age1 ? "男":"女");

int b1 = 10;
int b2 = 20;
int b3 = 30;
//           b2 > b3 ? b2:b3  如果b2大于b3 返回b2 否则返回b3
int max = (b1 > b2 ? b1:b2) > (b2 > b3 ? b2: b3) ? (b1 > b2 ? b1:b2) : (b2 > b3 ? b2: b3);
System.out.println("最大值是：" + max);