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我們的任務是檢索文件並對其進行分類並將其顯示在另一個文件中。姓氏名，然後等級。循環標記器和記事本顯示
我有得到一個循環，因爲錯誤
"java.util.NoSuchElementException"
這要去麻煩，只有當我改變目前存在的，而我環路我有發生。我也有顯示結果的問題。我展示的結果都在一行中，我不能讓它發生。這裏是我的代碼到目前爲止：
import java.util.*;
import java.util.StringTokenizer;
import java.io.*;
import javax.swing.*;
import java.text.DecimalFormat;
class Grade
{
public static void main(String [] args)throws IOException
{
//declaring
String line = "";
StringTokenizer st;
String delim = " \t\n\r,-";
String token;
String firstname;
String lastname;
String grade;
String S69andbelow="Students with 69 or below\n";
String S70to79 ="Students with 70 to 79\n";
String S80to89= "Students with 80 to 89\n";
String S90to100= "Students with 90 to 100\n";
int gradeint;
double gradeavg = 0;
int count = 0;
File inputFile = new File("input.txt");
File outputFile = new File("output.txt");
FileInputStream finput = new FileInputStream(inputFile);
FileOutputStream foutput = new FileOutputStream(outputFile);
FileReader reader = new FileReader(inputFile);
BufferedReader in = new BufferedReader(reader);
Scanner std = new Scanner(new File("input.txt"));
Scanner scanner = new Scanner(inputFile);
BufferedWriter out = new BufferedWriter(new FileWriter(outputFile));
Scanner scan = new Scanner(S69andbelow);
//reading linev
line = scanner.nextLine();
st = new StringTokenizer(line, delim);
//avoiding selected characters
try
{
while(st.hasMoreTokens())
{
firstname = st.nextToken(); //<----error started to happen
lastname = st.nextToken(); //here
grade = st.nextToken(); //and here
//storing tokens into their properties
gradeint = Integer.parseInt(grade);
//converting token to int
gradeavg = gradeavg + gradeint;
//calculating avg
count++;
//recording number of entries
if (gradeint <=69)
{
S69andbelow = S69andbelow + lastname + " "
+ firstname + " " + "\t" + grade + "\n";
} // saving data by grades
else if (gradeint >= 70 && gradeint <= 79)
{
S70to79 = S70to79 + lastname + " " + firstname
+ " " + "\t" + grade + "\n";
} // saving data by grades
else if (gradeint >= 80 && gradeint <=89)
{
S80to89 = S80to89 + lastname + " " + firstname
+ " " + "\t" + grade + "\n";
} // saving data by grades
else
{
S90to100 = S90to100 + lastname + " " + firstname
+ " " + "\t" + grade + "\n";
} // saving data by grades
}//end while
System.out.println(S69andbelow + "\n" + S70to79 + "\n"
+ S80to89 + "\n" + S90to100);
//caterorizing the grades
gradeavg = gradeavg/count;
//calculating average
DecimalFormat df = new DecimalFormat("#0.00");
out.write("The average grade is: "
+ df.format(gradeavg));
System.out.println("The average grade is: "
+ df.format(gradeavg));
Writer output = null;
output = new BufferedWriter(new FileWriter(outputFile));
// scanner.nextLine(S69andbelow);
//output.write(S69andbelow + "\n" + S70to79 + "\n"
// + S80to89 + "\n" + S90to100);
// output.close();
}
catch(Exception e)
{
System.out.println(e.toString());
}
// Close the stream
try
{
if(std != null)
std.close();
}
catch(Exception e)
{
System.out.println(e.toString());
}
}
}
已回答問題。最後的潤色，作爲介紹： /* ** * ** * ** * ** * ** * ** * 程序名稱：等級 姓名：Dennis Liang 交期：2011年3月31日 程序描述：編寫程序 從文件中讀取 學生的列表及其成績。還顯示 姓氏，名字，然後等級。 * ** * ** * ** * ** * ** * ****/
進口java.util中。 ; import java.util.StringTokenizer; import java.io.; import javax.swing。*; import java.text.DecimalFormat;
類 級{ 公共靜態無效的主要（字串[] args）拋出IOException異常
{
//declaring
String delim = " \t\n\r,-";
String token;
String firstName;
String lastName;
String grade;
String S69andbelow="Students with 69 or below\n";
String S70to79 ="Students with 70 to 79\n";
String S80to89= "Students with 80 to 89\n";
String S90to100= "Students with 90 to 100\n";
String all;
int gradeint;
double gradeavg = 0;
int count = 0;
int countTwo = 0;
File inputFile = new File("input.txt");
File outputFile = new File("output.txt");
FileInputStream finput = new FileInputStream(inputFile);
FileOutputStream foutput = new FileOutputStream(outputFile);
FileReader reader = new FileReader(inputFile);
BufferedReader in = new BufferedReader(reader);
Scanner std = new Scanner(new File("input.txt"));
Scanner scanner = new Scanner(inputFile);
BufferedWriter out = new BufferedWriter(new FileWriter(outputFile));
Scanner scan = new Scanner(S69andbelow);
try
{
String line, newLine = (String)System.getProperty("line.separator");
//seperating lines
while((line = in.readLine()) != null){
//Will only work if the file is properly formatted
StringTokenizer st = new StringTokenizer(line, " ");
if (st.countTokens() == 3)
{
firstName = st.nextToken();
lastName = st.nextToken();
grade = st.nextToken();
gradeint = Integer.parseInt(grade);
//retrieving tokens
gradeavg = gradeavg + gradeint;
//formula for avg
count++;
//avg count
//organizing by grades
if (gradeint <=69)
{
S69andbelow = S69andbelow + newLine+ lastName + " "
+ firstName + " " + "\t" + grade + newLine;
}
else if (gradeint >= 70 && gradeint <= 79)
{
S70to79 = S70to79 +newLine+ lastName + " " + firstName
+ " " + "\t" + grade + newLine;
}
else if (gradeint >= 80 && gradeint <=89)
{
S80to89 = S80to89 + newLine+ lastName + " " + firstName
+ " " + "\t" + grade + newLine;
}
else
{
S90to100 = S90to100 + newLine+ lastName + " " + firstName
+ " " + "\t" + grade + newLine;
}
} 否則{ countTwo ++; System.out.println（「有+ countTwo +」person/people「+ 」需要附加信息「+」\ n「）; }//通知用戶有多少人 }//缺少信息或太多。
System.out.println(S69andbelow + "\n" + S70to79 + "\n"
+ S80to89 + "\n" + S90to100);
//caterorizing the grades
gradeavg = gradeavg/count;
//calculating average
DecimalFormat df = new DecimalFormat("#0.00");
//formating
System.out.println("The average grade is: "
+ df.format(gradeavg));
//displaying
Writer output = null;
output = new BufferedWriter(new FileWriter(outputFile));
//make file
output.write(newLine + S69andbelow + newLine + S70to79 + newLine
+ S80to89 + newLine + S90to100);
output.write("The average grade is: "
+ df.format(gradeavg));
//outputing to file
output.close();
//saving
} 趕上（例外五） {
的System.out.println（e.toString（））; （標準差=空） std。關（ ）;
}
catch(Exception e)
{
System.out.println(e.toString());
}
}}
您可能想添加「家庭作業」標籤。 – louisgab 2011-04-07 03:04:22
您能至少張貼發生異常的行號，可能是堆棧跟蹤的一部分嗎？ – R0MANARMY 2011-04-07 03:30:30
我評論了它在編碼中的位置。 – dennis 2011-04-07 03:35:56