没有小数点打印

Question

所以我试图找到 class.. 中的出勤率。使用 attend=total present / tot students.. 由于某种原因，我一直得到零的答案。我将 attend 变量初始化为 double。在有人回答之前，我总是想明确这是作业。我有一段时间很忙，因为我似乎无法像通常对 C++ 那样使用编译器进行调试，所以如果有人对 IDE 有任何建议，我也将非常感谢您的帮助。我的代码如下

 tot_stu+=students;
 tot_pres+=present;
 absent = tot_stu - tot_pres;
 attend = tot_pres / tot_stu;

 //test

 System.out.println(tot_stu);
 System.out.println(tot_pres);
 System.out.println(attend);

 //output
 System.out.println("The school has " +tot_stu+ " students");
 System.out.println("The school has " +tot_pres+ " students present");
 System.out.println("The school has "+absent+" students absent");
 System.out.println("The schools over all attendence rate is: " + attend);
 System.out.println("");

我不断得到这个输出

 Please enter the total number of classes: 2
 Enter the total students in class 1:10
  Enter how many students were present in class 1: 5
 10
 5
 0.0
 The school has 10 students
 The school has 5 students present
 The school has 5 students absent
 The schools over all attendance rate is: 0.0

 Enter the total students in class 2: 65
 Enter how many students were present in class 2: 7
 65
 7
 0.0
 The school has 65 students
 The school has 7 students present
 The school has 58 students absent
 The schools over all attendance rate is: 0.0

Answer 1

问题是您可能将 int 用于 tot_pres 和 tot_stu。要修复，请将您的行更改为：

 attend = tot_pres / (tot_stu+0.0);

或

 attend = tot_pres / ((double)tot_stu);

或任何其他变体！唯一吐出结果 int 值的是当分母和分子都为 int.

时

执行此操作时，编译器会将分母读取为 double 而不是 int。

Answer 2

确保 tot_pres 或 tot_stu 是双倍的。或者您可以简单地执行以下操作.. ((双)tot_pres)/tot_stu;

Answer 3

确保您使用的是浮点类型而不是 int。 attend 必须是浮点类型如果 tot_pres 和 tot_stu 是整数，则在除法时将它们转换为浮点数：

attend = (double)tot_pres /tot_stu;

Answer 4

如果你用这个替换部分代码会发生什么？

double attend;
int total_students = 2;
int total_present = 10;
attend = total_present/total_students;

没有小数点打印

not getting a decimal to print

java

decimal