>[success] # if /else if /if -- 判斷 * `條件` 判斷條件表達式是否成立 ~~~ if (條件) { // 條件滿足時執行 語句塊1; }else if(條件){ // 條件滿足時執行 語句塊2; }else{ // 條件滿足時執行 語句塊3; } ~~~ >[danger] ##### 判斷考試成績 ~~~ import java.util.Scanner; public class IfTest { public static void main(String[] args) { System.out.println("輸入考試成績"); // 獲取成績 Scanner sc = new Scanner(System.in); int scores = sc.nextInt(); if (scores >= 90) { System.out.println("成績優秀" ); } else if (scores >= 60) { System.out.println("成績及格"); } else { System.out.println("成績不及格"); } } } ~~~ >[danger] ##### 稅率計算 ~~~ import java.util.Scanner; public class IfTest { public static void main(String[] args) { System.out.println("工資"); Scanner sc = new Scanner(System.in); // 輸入工資 int salary = sc.nextInt(); // 交稅金額 double 類型 double salaryPrice = 0.0; if (salary <= 5000) { } else if (salary <= 8000) { salaryPrice = (salary - 5000) * 0.03; } else if (salary <= 17000) { salaryPrice = (salary - 5000) * 0.1 - 210; } else if (salary <= 30000) { salaryPrice = (salary - 5000) * 0.2 - 1410; } System.out.println(salaryPrice); } } ~~~