运算符

public class Demo01 {
    public static void main(String[] args) {
        //二元运算符
        int a = 10;
        int b = 20;
        int c = 30;
        int d = 40;
        System.out.println(a+b);
        System.out.println(a-b);
        System.out.println(a*b);
        System.out.println(a/(double)b);//出现小数时把数据类型强转
    }
}

public class Demo02 {
    public static void main(String[] args) {
        long a = 123123123123L;
        int b = 123;
        short c = 10;
        byte d = 8;

        System.out.println(a +b +c +d);
        System.out.println(b +c +d);
        System.out.println(c +d);
    }
}

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\
        //if
        int a = 10;
        int b = 20;
        int c = 21;

        System.out.println(c%a);// c/a  21/10 = 2 ....1

        System.out.println(a>b);
        System.out.println(a<b);
        System.out.println(a==b);
        System.out.println(a!=b);
    }
}