java - Java 中的成绩报告
问题描述
我正在尝试创建一个为学生生成成绩报告的程序。我想问以下问题:
1 - 当我运行程序时,我在线程“main” java.util.InputMismatchException 中遇到问题异常(请参阅下文了解详细信息)。
2 - 如何将输出格式化为表格?我计划有 5 列:班级、描述、单位、成绩和成绩点。我无法让表格中的内容与标题(类、描述、单位等)对齐
import java.util.*;
public class Project1 {
public static void main(String args[])
{
Scanner scanner = new Scanner(System.in);
//Input the term
System.out.println("Please enter the term of your grade calculation (for example, Fall 2015): ");
String term = scanner.nextLine();
//Input the number of courses that the student is enrolled in
System.out.println("Please enter the number of courses that you are enrolled in "+term+": ");
int numberofcourses = scanner.nextInt();
//Declaration
String a[] = new String[numberofcourses];
//Arrays for class number, description, units, grade, grades point
//Here, input class number, description, units, and grades
for(int i = 0; i < numberofcourses; i++)
{
System.out.println("Please enter the #"+(i+1)+" class name: ");
String ClassName = scanner.nextLine();
scanner.hasNextLine();
System.out.println("Please enter the #"+(i+1)+" description: ");
String Description = scanner.nextLine();
scanner.hasNextLine();
System.out.println("Please enter the #"+(i+1)+" units: ");
int Units = scanner.nextInt();
scanner.hasNextLine();
int Grades = scanner.nextInt();
scanner.hasNextLine();
}
System.out.println("Class Grades - "+term+" Term");
System.out.println("Office Grades");
System.out.println("Class \t \t Description \t \t Units \t \t Grade \t \t Grade Points");
for(int i = 0; i < numberofcourses; i++)
{
System.out.println(a[i] + "\t \t");
}
}
}
输出:
Please enter the term of your grade calculation (for example, Fall 2015):
Fall 2016
Please enter the number of courses that you are enrolled in Fall 2016:
2
Please enter the #1 class name:
COMPSCI 172
Please enter the #1 description:
Computer Science
Please enter the #1 units:
Exception in thread "main" java.util.InputMismatchException
at java.base/java.util.Scanner.throwFor(Scanner.java:939)
at java.base/java.util.Scanner.next(Scanner.java:1594)
at java.base/java.util.Scanner.nextInt(Scanner.java:2258)
at java.base/java.util.Scanner.nextInt(Scanner.java:2212)
at Project1.main(Project1.java:29)
解决方案
所以首先你有很多东西需要修复,包括我将为你修复的东西。如果要在最后一起输出所有类,则必须编辑我的代码以将格式化的字符串存储在数组中,然后将它们全部输出。
scanner.nextLine();
我通过在您的行后添加来修复您的错误int numberofcourses = scanner.nextInt();
。您需要这样做,因为scanner.nextInt()
不会消耗行终止符并移至下一行,因此这意味着您的下一个nextLine()
将搞砸并尝试读取任何内容。这个额外的行确保Scanner
将移动到下一行。
继续前进,你有一大堆使用不当的scanner.hasNextLine();
. 这将返回一个布尔条件,让您知道下一行是否存在。您目前不使用此布尔条件,只是让它什么都不做。如果要使用它,则需要在if
语句或while
循环中使用它。我删除了所有这些行。
最后格式化您的打印语句使用String.format()
. 下面显示了我为输出您的值所做的示例。您可以将其存储到一个String
数组中,稍后将它们一起输出。如果您有任何其他问题,请告诉我。这是完整的代码(我测试过它运行良好):
Scanner scanner = new Scanner(System.in);
//Input the term
System.out.println("Please enter the term of your grade calculation (for example, Fall 2015): ");
String term = scanner.nextLine();
//Input the number of courses that the student is enrolled in
System.out.println("Please enter the number of courses that you are enrolled in "+term+": ");
int numberofcourses = scanner.nextInt();
scanner.nextLine();
//Declaration
String a[] = new String[numberofcourses];
//Arrays for class number, description, units, grade, grades point
//Here, input class number, description, units, and grades
for(int i = 0; i < numberofcourses; i++)
{
System.out.println("Please enter the #"+(i+1)+" class name: ");
String ClassName = scanner.nextLine();
System.out.println("Please enter the #"+(i+1)+" description: ");
String Description = scanner.nextLine();
System.out.println("Please enter the #"+(i+1)+" units: ");
int Units = scanner.nextInt();
System.out.println("Please enter the #"+(i+1)+" grades: ");
int Grades = scanner.nextInt();
System.out.println("Class Grades - "+term+" Term");
System.out.println("Office Grades");
System.out.println(String.format("Class: %s Description: %s Units: %d Grade: %d Grade Points", ClassName, Description, Units, Grades));
}
这是我的控制台的样子:
Please enter the term of your grade calculation (for example, Fall 2015):
Fall 2012
Please enter the number of courses that you are enrolled in Fall 2012:
1
Please enter the #1 class name:
Comp Sci 2001
Please enter the #1 description:
Computer Science
Please enter the #1 units:
3
Please enter the #1 grades:
95
Class Grades - Fall 2012 Term
Office Grades
Class: Comp Sci 2001 Description: Computer Science Units: 3 Grade: 95 Grade Points
显然,输出可以以您喜欢的任何方式进行格式化,这只是一个快速模型。
推荐阅读
- java - 我有两个具有相同内容但具有不同哈希码的字符串,因此 .equals 方法返回错误。请建议如何解决这个问题
- reactjs - 在第三方网站上渲染 React Widget
- java - 使 ValueListener 只发生一次
- dialogflow-es - 如何将图像添加到谷歌轮播上的操作?
- php - 将表单数据附加到以前的帖子
- r - 如何用行和列中的变量/观察重新排列数据框?(使用 dplyr 和 tidyr)
- html - 用于医疗诊断的 HTML 表格
- excel - excel if函数在某些情况下返回非常奇怪的数字
- r - 在 macOS 10.14.1 上为 R 安装 Rattle 时出现错误消息
- python - 类内字典使用,名称未定义