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我試圖，因爲「加」和元素，而不是檢查大小，然後動態地每次一個新元素輸入一個擴展陣列的功能，創建一個列表。我無法得到這個編譯。我搜索了堆棧和谷歌，沒有發現我正在幫助我。有人提到創建一個數組，並使用它添加到列表中，但在我看來，我應該能夠做到這一點，沒有這一切。列表和ArrayList初始化和使用
我試圖讓系統中的每一個確定的結果發生時間的字符串添加到列表中。
爲了便於查找列表被稱爲 「不正確」
import java.text.DecimalFormat;
import java.util.*;
public class User{
private String wrongQuestion; //quiz question
private String userName; //store user name
private String myOutput; //store output for toString and file write
private int score; //store user current score
private float average; //store user average score
private int diffLevel; //difficulty level
private int testType; //last test type
private int numTests; //store number of tests taken
private List <String> incorrect; //declare list for incorrect answers
private FileIO uFile; //declare FileIO object
public User(String inName) throws Exception
{
//local constants
final int VARIABLE_COUNT = 5; //loop sentinel
final int TOKEN_SKIP = 4; //loop sentinel
//local variables
int index; //loop index
int count; //loop counter
String token; //store tokens from line
StringTokenizer tokenLine; //store tokenized line
//instantiate file object
uFile = new FileIO (inName);
//if user exists
if (uFile.checkUser())
{
for (count = 0; count < VARIABLE_COUNT; count++)
{
//initialize tokenized line
tokenLine = new StringTokenizer(uFile.readLine());
//try to store the variables
try
{
//get and store user average
//for the first 2 tokens, skip
for (index = 0; index < TOKEN_SKIP; index++)
{
//move to next token
token = tokenLine.nextToken();//end for
switch (count)
{
case 1:
//store number of tests taken
numTests = Integer.parseInt(token);
//end case
break;
case 2:
//store difficulty of last test taken
diffLevel = Integer.parseInt(token);
//end case
break;
case 3:
//store score of last test taken
score = Integer.parseInt(token);
//end case
break;
case 4:
//store average of tests taken
average = Integer.parseInt(token);
//end case
break;
default:
break;
}//end switch
}//end for
//store next line
token = uFile.readLine();
//while there are more lines in the file
while (token != null)
{
//instantiate list for incorrect answers
incorrect = new ArrayList<String>();
//add line to end of list
incorrect.get(token);
//store next line
token = uFile.readLine();
}//end while
}//end try
//catch input mismatch exception
catch (InputMismatchException error)
{
//output error message
System.out.println ("This file is not formatted properly." +
" Either continue as a new user or log in again");
//initialize data to 0
average = 0;
testType = 0;
diffLevel = 0;
numTests = 0;
incorrect = new ArrayList <String>();
}//end catch
}//end for
}//end if
else
{
//initialize data to 0
average = 0;
testType = 0;
diffLevel = 0;
numTests = 0;
incorrect = new ArrayList<String>();
}//end else
//close input stream
uFile.closeFileReader();
}//end constructor
public float calcAverage(int newScore)
{
//local constants
//local variables
float avg; //store temp average
/**************Begin calcAverage*********/
//recalibrate avg for new calculation
avg = 0;
//calculate new average test score
avg = ((average * numTests) + newScore)/(numTests + 1);
//return average to be stored
return avg;
}
public void updateUser(int newTestType, int newDiffLevel, int newScore)
{
//local constants
//local variables
/***************Begin updateUser************/
//update new data after test is taken
score = newScore;
average = calcAverage(newScore);
diffLevel = newDiffLevel;
testType = newTestType;
numTests = numTests + 1;
}
public void writeFile() throws Exception
{
//local constants
//local variables
String line; //current line to write to file
int index; //loop index
/*************************Begin writeFile***************/
//open output stream
uFile.openOutput(userName);
//write user name
line = "User Name:\t" + userName +"\n";
uFile.writeLine(line);
//write number of tests taken
line = "Tests Taken:\t" + numTests + "\n";
//write number of tests taken
line = "Difficulty Level:\t" + diffLevel + "\n";
uFile.writeLine(line);
//write score of last test taken
line = "Last Test:\t" + score + "\n";
uFile.writeLine(line);
//write current user average
line = "User Average:\t" + average + "\n";
uFile.writeLine(line);
//for each element in the list
for (index = 0; index < incorrect.size(); index++)
{
//store then write the string
line = incorrect.get(index);
uFile.writeLine(line);
}//end for
//close file writer
uFile.closeFileWrite();
}//end writeFile
public void storeIncorrect(String inString)
{
//local constants
//local variables
/************Begin storeIncorrect*************/
//add formatted question to the list
incorrect.add(inString);
}
public String toString()
{
//local constants
//local variables
String buildUserName;
String buildAvg;
String buildNumTests;
String buildDiffLevel;
String buildScore;
DecimalFormat fmt; //declare decimal format object
/****************Begin toString***********/
//initialize decimal format
fmt = new DecimalFormat ("0.00");
//build output strings
buildUserName = Util.setLeft(20, "User Name:") + Util.setRight(25, userName);
buildNumTests = Util.setLeft(20, "Tests Taken:") + Util.setRight(18, numTests+"");
buildDiffLevel = Util.setLeft(20, "Last Difficulty:") + Util.setRight(24, diffLevel+"");
buildScore = Util.setLeft(20, "Last Score:") + Util.setRight(24, score+"");
buildAvg = Util.setLeft(20, "Test Average:") + Util.setRight(24, fmt.format(average)+"");
myOutput = buildUserName + "\n" + buildNumTests + "\n" + buildDiffLevel + "\n" + buildScore + "\n" + buildAvg;
return myOutput;
}//Display all users info
}
所以其位編譯器窒息？ –
無法解析'FileIO'類，因爲它不包含在您的示例中。 – HAL