接上一篇說到的選擇結構，除了if(單一選擇敘述)還有其他的選擇敘述，下面繼續講
if-else雙向選擇敘述
當if條件運算式不成立，執行else下的程式

import java.util.Scanner;

public class passExam {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Please enter the score: "); 
        int score = scanner.nextInt();
        

        if(score >= 60) // greater than 60
            System.out.println("pass"); 
        else 
            System.out.println("Failed"); 
    }
}

else if 的條件敘述
設定多個條件來配合複雜的規則來執行敘述

import java.util.Scanner;

public class ScoreLevel {
    public static void main(String[] args) 
    {
        Console console=System.console();
        int Score;
        System.out.print("Please enter the score: ");
        Score=Integer.parseInt(console.readLine());
        if(Score<60) { System.out.println("E(Failed)"); }
        else if(Score>=60&&Score<=69) { System.out.println("D"); }
        else if(Score>=70&&Score<=79) { System.out.println("C"); }
        else if(Score>=80&&Score<=89) { System.out.println("B"); }
        else if(Score>=90) { System.out.println("A"); }
        else { System.out.println("Cannot identify"); }
    }
}
        

多向選擇敘述(switch-case敘述)
switch 是一種多選一的敘述，每一個case跟隨著一個條件，當條件成立執行敘述

switch(變數名稱或運算式) { 
    case 條件一: 
        敘述一; 
        break; 
    case 條件二: 
        敘述二; 
        break; 
    default: 
        敘述三; 
 } 

public class SwitchExample {
    public static void main(String[] args) {
        int dayOfWeek = 3; // Suppose it's Wednesday

        String dayName;

        switch (dayOfWeek) {
            case 1:
                dayName = "Monday";
                break;
            case 2:
                dayName = "Tuesday";
                break;
            case 3:
                dayName = "Wednesday";
                break;
            case 4:
                dayName = "Thursday";
                break;
            case 5:
                dayName = "Friday";
                break;
            case 6:
                dayName = "Saturday";
                break;
            case 7:
                dayName = "Sunday";
                break;
            default:
                dayName = "Invalid day";
                break;
        }

        System.out.println("The day is " + dayName);
    }
}