HOW2J——JAVA基础——运算符、控制流程

1、运算符

import java.util.Scanner;public class Operator {public static void main(String[] args) {Scanner input=new Scanner(System.in);//使用Scanner从控制台获取两个数字，然后计算这两个数字的和,比较大小System.out.print("请输入第一个整数:");int firstNumber=input.nextInt();System.out.print("请输入第二个整数:");int secondNumber=input.nextInt();System.out.println("两个数的和是："+(firstNumber+secondNumber));System.out.println("firstNumber<secondNumber:"+(firstNumber<secondNumber));//自增运算符练习int i = 1;int j = ++i + i++ + ++i + ++i + i++;System.out.println("i="+i+",j="+j);//计算BMISystem.out.print("请输入身高（m)：");double height=input.nextDouble();System.out.print("请输入体重（kg)：");double weight=input.nextDouble();System.out.println("您的BMI是："+weight/(height*height));//逻辑运算符int a = 1;boolean b = !(a++ == 3) ^ (a++ ==2) && (a++==3);System.out.println(b);System.out.println(a);//三元运算符，今天是星期几System.out.print("今天是星期几？请输入一个整数:");int day=input.nextInt();String week=(day>=1&&day<=7)?(day<=5?"工作日":"周末"):"输入错误";System.out.println(week);}}

2、控制流程

import java.util.Scanner;public class ControlFlow {public static void main(String[] args) {Scanner input=new Scanner(System.in);//判断是否是闰年System.out.print("请输入年份");int year=input.nextInt();String leapYear=(year%4==0&&year%100!=0||year%400==0)?"是闰年":"不是闰年";System.out.println(year+leapYear);//输入月份判断季节System.out.print("请输入月份：");int month=input.nextInt();switch((month-1)/3){case 0:System.out.println("春天");break;case 1:System.out.println("夏天");break;case 2:System.out.println("秋天");break;case 3:System.out.println("冬天");break;default:System.out.println("输入非法");}//计算一个数的阶乘System.out.print("请输入一个数：");long num=input.nextLong();long i=num;long factorial=1;while(i>1){factorial*=i--;}System.out.println(num+"的阶乘是："+factorial);//求乞丐的总收入，即求等比数列的和int dayIncome=1;int sumIncome=1;for(int day=2;day<=10;day++){dayIncome*=2;sumIncome+=dayIncome;}System.out.println("洪乞丐干十天的总收入："+sumIncome);}}