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java 编写一个包含 while 循环代码的程序来计算用户输入的考试分数数量

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时间：2020-11-02 15:39:36 　来源:igfitidea点击:

Write a program with while loop code in it to calculate the amount of exam scores enter by a user

javaif-statementwhile-loopdo-while

提问by Evert Van Eeden

I wrote a program for the following question in a task I'm doing.

我在我正在做的任务中为以下问题编写了一个程序。

"Write a program to read a list of exam scores given as integer percentages in the range 0 to 100. Display the total number of grades and the number of grades in each letter-grade category as follows: 90-100 is A, 80-89 is B, 70-79 is C, 60-69 is D, and 0-59 is F. Use negative score as a sentinel value to indicate the end of the input."

“编写一个程序来读取以 0 到 100 范围内的整数百分比给出的考试分数列表。显示总成绩数和每个字母等级类别的成绩数如下：90-100 是 A，80- 89 是 B，70-79 是 C，60-69 是 D，0-59 是 F。使用负分数作为哨兵值来表示输入的结束。”

For Example, input: 98,87,86,85,85,78,73,72,72,70,66,63,50,-1

例如输入：98,87,86,85,85,78,73,72,72,70,66,63,50,-1

Output should be:

输出应该是：

Total number of grades entered was 13

输入的成绩总数为 13

A's =1

A = 1

B's=4

B's=4

C's=5

Cs=5

D's=2

Ds=2

F's=1

Fs=1

//This is the code I wrote.// 
import java.util.Scanner;
public class grade
 {
public static void main(String[] args)
 {
        int A_grades = 0;
        int B_grades = 0;
        int C_grades = 0;
        int D_grades = 0;
        int F_grades = 0;
        int count=0;
        Scanner in = new Scanner(System.in);
        System.out.println("Enter exam score as integer percentage in range 0 to 100 :");
        int score = in.nextInt();
 while(score>0)
 {
       count++;
 if(score>=90 && score<=100)
        A_grades++;
    else if(score>=80 && score<=89)
        B_grades++;
    else if(score>=70 && score<=79)
        C_grades++;
    else if(score>=60 && score<=69)
        D_grades++;
    else if(score>=0 && score<=59)
        F_grades++;
    System.out.println("Enter exam score as integer percentage in range 0 to 100 :");
 score = in.nextInt();
 } //end while
 System.out.println("Total number of grades :"+ count);
 System.out.println("Total number of A grades :"+ A_grades);
 System.out.println("Total number of B grades :"+ B_grades);
 System.out.println("Total number of C grades :"+ C_grades);
 System.out.println("Total number of D grades :"+ D_grades);
 System.out.println("Total number of F grades :"+ F_grades);
 } // end main
 } // end class

Below is the Output of the program.

下面是程序的输出。

Enter exam score as integer percentage in range 0 to 100 :

以 0 到 100 范围内的整数百分比形式输入考试分数：

88 98 78 68 55 45 -1

88 98 78 68 55 45 -1

Enter exam score as integer percentage in range 0 to 100 :

以 0 到 100 范围内的整数百分比形式输入考试分数：

Enter exam score as integer percentage in range 0 to 100 :

以 0 到 100 范围内的整数百分比形式输入考试分数：

Enter exam score as integer percentage in range 0 to 100 :

以 0 到 100 范围内的整数百分比形式输入考试分数：

Enter exam score as integer percentage in range 0 to 100 :

以 0 到 100 范围内的整数百分比形式输入考试分数：

Enter exam score as integer percentage in range 0 to 100 :

以 0 到 100 范围内的整数百分比形式输入考试分数：

Enter exam score as integer percentage in range 0 to 100 :

以 0 到 100 范围内的整数百分比形式输入考试分数：

Total number of grades :6

总年级数：6

Total number of A grades :1

A级总数：1

Total number of B grades :1

B级总数：1

Total number of C grades :1

C级总数：1

Total number of D grades :1

D级总数：1

Total number of F grades :2

F级总数：2

In the output it keeps repeating "Enter exam score as integer percentage in range 0 to 100 :"

在输出中，它不断重复“以 0 到 100 范围内的整数百分比形式输入考试分数：”

How can I write the code to only show it once?

如何编写代码只显示一次？

回答by Eran

Remove System.out.println("Enter exam score as integer percentage in range 0 to 100 :");from your loop if you don't want to see this message multiple times.

System.out.println("Enter exam score as integer percentage in range 0 to 100 :");如果您不想多次看到此消息，请从循环中删除。

回答by TejjD

the reason it is continuously printing that out is because the "Scanner" class that you are using does not pause for input.

它不断打印出来的原因是因为您使用的“扫描仪”类不会暂停输入。

I would suggest that you use a BufferedReader.

我建议您使用 BufferedReader。

I assume that you need to ask the user to enter a value each time. So if you remove the text to solve the multiple display issue, the user wont be given the message.

我假设您每次都需要要求用户输入一个值。因此，如果您删除文本以解决多重显示问题，则不会向用户提供消息。

I have attached a snippet of the code, with a BufferedReader that will solve your problem:

我附上了一段代码，带有 BufferedReader 可以解决您的问题：

//This is the code I wrote.// 
import java.util.Scanner;
import java.io.*;
import java.io.BufferedReader;
import java.util.*;

public class Grade{
 public static void main(String[] args){
  int A_grades = 0;
  int B_grades = 0;
  int C_grades = 0;
  int D_grades = 0;
  int F_grades = 0;
  int count=0;
  try{
   //Scanner in = new Scanner(System.in);
   BufferedReader br = new BufferedReader(new InputStreamReader(System.in) );
   System.out.println("Enter exam score as integer percentage in range 0 to 100 :");
   int score = Integer.parseInt(br.readLine());
   while(score>0){
    count++;
    if(score>=90 && score<=100)
     A_grades++;
    else if(score>=80 && score<=89)
     B_grades++;
    else if(score>=70 && score<=79)
     C_grades++;
    else if(score>=60 && score<=69)
     D_grades++;
    else if(score>=0 && score<=59)
     F_grades++;
    System.out.println("Enter exam score as integer percentage in range 0 to 100 :");
    score = Integer.parseInt(br.readLine());
   } //end while
  }catch(IOException ioe){}
  System.out.println("Total number of grades :"+ count);
  System.out.println("Total number of A grades :"+ A_grades);
  System.out.println("Total number of B grades :"+ B_grades);
  System.out.println("Total number of C grades :"+ C_grades);
  System.out.println("Total number of D grades :"+ D_grades);
  System.out.println("Total number of F grades :"+ F_grades);
 } // end main
} // end class

Hope this helps you and answers your question :)

希望这可以帮助您并回答您的问题:)

Let me know of the outcome

让我知道结果

回答by Evert Van Eeden

Thank you for all the answers.

谢谢大家的回答。

This is the final code and it works perfectly.

这是最终的代码，它完美地工作。

 import java.util.Scanner;
public class grade
 {
 public static void main(String[] args)
 {
        int A_grades = 0;
        int B_grades = 0;
        int C_grades = 0;
        int D_grades = 0;
        int F_grades = 0;
    int count=0;
    Scanner in = new Scanner(System.in);
    System.out.println("Enter exam score as integer percentage in range 0 to 100");
    System.out.println("And enter a negative score at the end of the list :");
    int score = in.nextInt();
 while(score>0)
     {
       count++;
 if(score>=90 && score<=100)
        A_grades++;
    else if(score>=80 && score<=89)
        B_grades++;
    else if(score>=70 && score<=79)
        C_grades++;
    else if(score>=60 && score<=69)
        D_grades++;
    else if(score>=0 && score<=59)
        F_grades++;
    score = in.nextInt();
 } //end while
 System.out.println("Total number of grades :"+ count);
 System.out.println("Total number of A grades :"+ A_grades);
 System.out.println("Total number of B grades :"+ B_grades);
 System.out.println("Total number of C grades :"+ C_grades);
 System.out.println("Total number of D grades :"+ D_grades);
 System.out.println("Total number of F grades :"+ F_grades);
 } // end main
 } // end class