import java.util.Scanner; public class Main{ public static void main(String []args){ Scanner sc = new Scanner(System.in); int a = sc.nextInt(); int b = sc.nextInt(); int c = sc.nextInt(); System.out.printf("%.6f",(a + b + c) / 3.0); } }这题先计算三个数的和,在除以3.0转为浮点数。