Java流程控制_选择结构

选择结构

本文md文件

if单选择结构

import java.util.Scanner;

public class Day3 {
    public static void main(String[] args) {
        System.out.println("请输入一个大于零小于十的数字");
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        if (a >= 6 & a <= 10) {
            System.out.println("合格");
        }
        System.out.println("END");
        scanner.close();
    }
}

if双选择结构

import java.util.Scanner;

public class Day3 {
    public static void main(String[] args) {
        System.out.println("请输入一个大于零小于十的数字");
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        if (a=<10&a>0&a>=6){
            System.out.println("成功");
        }else {
            System.out.println("不属于0-10的范围");
        }
        scanner.close();
    }
}

if多选择结构

import java.util.Scanner;

public class Day3 {
    public static void main(String[] args) {
        System.out.println("请输入一个大于零小于十的数字");
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        if (a<10&a>6){
            System.out.println("成功");
        }else if (a<=6&a>3){
            System.out.println("运气好");
        }else if (a>0&a<=3){
            System.out.println("点背");
        }else {
            System.out.println("不属于0-10的范围");
        }
        scanner.close();
    }
}

嵌套的if结构

import java.util.Scanner;

public class Day3 {
    public static void main(String[] args) {
        System.out.println("请输入一个值");
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        if (a>3){
            System.out.println("大于3");
            if (a>6){
                System.out.println("大于6");
            }
        }
        scanner.close();
    }
}

switch多选择结构

public class Day3 {
    public static void main(String[] args) {
        System.out.println("请输入一个值");
        char grade = 'C';//JDK7之后支持String的比较，和char方法同
        switch (grade){
            case 'A':
                System.out.println("有效");
                break;//可选，如不加break会发生case穿透，将寻找到的值和后面的值全部输出
            case 'B':
                System.out.println("有效");
                break;
            case 'C':
                System.out.println("有效");
                break;
            case 'D':
                System.out.println("有效");
                break;
            default://相当于else
                System.out.println("未知");
        }
    }
}