public class ScannnerDemo { public static void main(String[] args){ Scanner scann = ?new Scanner(System.in); double sum = 0; ? ? ? ? ?int m = 0;? while(scann.hasNextDouble()) { double x = scann.nextDouble(); m = m+1; sum = sum+x; } System.out.println(m+"個數的和是"+sum); System.out.println(m+"個數的平均數是"+sum/m);}}問題描述：我把while換成if ?如圖結果為：可while與if邏輯上不一樣嗎？為毛執行結果這么大差別。