Java printf用于求和和平均值

Question

这是我所拥有的内容：

  double[] miles = new double [10];

  double milesPerWeek = 26.0 / 10;
  double totalMiles = 0;
  double sum = 0;
  double average = 0;

  System.out.println("Week\tMiles");

  for (int i = 0; i < miles.length; i++){

     miles[i] += milesPerWeek;
     totalMiles += miles[i];

     System.out.printf("Week %d\t%.1f%n", i + 1, totalMiles);
  }
  for (int i = 0; i < miles.length; i++)
  {              
     sum = sum + miles[i];
     average = sum / miles.length;
  }
  System.out.printf("The total of miles run is: %.1f%n" + sum + "\n");

  System.out.printf("The average of miles run is: %.1f%n" + average);

这是在使用求和和平均值时遇到的问题。我无法在不出现错误信息的情况下使用print f来格式化小数位： “跑步里程总计为：Exception in thread "main" java.util.MissingFormatArgumentException: Format specifier '%.1f'”

请指导我如何保留一位小数。

- Janine McDaniel

Answer 1

你需要将值作为参数传递，而不是将它们连接起来：

System.out.printf("The total of miles run is: %.1f%n\n", sum);

System.out.printf("The average of miles run is: %.1f%n", average);

- shmosel

Answer 2

System.out.println("Blah %.1f\n", sum);

- djechlin

Answer 3

你知道那种“啊哈！”的时刻吗？我刚刚经历了它……在格式化输出时，不应使用加号，而应该使用逗号！修正后的语法：

System.out.printf("The total of miles run is: %.1f%n", sum, "\n");

System.out.printf("The average of miles run is: %.1f%n", average);

- Janine McDaniel

---

%n 不是占位符用于替换你自己的行分隔符。它是用于替换操作系统的行分隔符的占位符。因此，在您的printf中添加第二个 "\n" 参数是没有意义的，因为它不会被使用。 - Pshemo