2021-04-18

package operator;

public class Dm01 {
public static void main(String[] args) {
//二元运算
//ctrl+D 复制当前行到下一行
int a = 20;
int b = 30;
int c = 40;
int d = 50;
System.out.println(a+b);
System.out.println(a-b);
System.out.println(a*b);
System.out.println(a/(double)b);

}

}

package operator;

public class Dm02 {
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); //有long类型，加后结果也为long
System.out.println(b+c+d);
System.out.println(c+d); // 相加都为int
}
}