为了使程序正常工作，我必须想办法重新打开最初是输出文件的文件。
我的程序需要先读取输入文件，然后再写入输出文件。
然后，我将提示用户在此处输入代码e选项以输入更多代码或从输出文件中搜索任何数据。
我的程序首先选择1插入更多数据，2搜索数据，3退出程序。
我可以在用户输入更多数据后关闭I / O文件，但是如果用户想先搜索数据怎么办？
if(readFile==0)
{
FileReader inFile = new FileReader("DATA4STUDENTS.txt");
BufferedReader br = new BufferedReader(inFile);
FileWriter fw1 = new FileWriter("PASSED_STUDENTS.txt");
BufferedWriter bw1= new BufferedWriter(fw1);//Files i want to write and read again later on in the same program.
FileWriter fw2 = new FileWriter("FAILED_STUDENTS.txt");
BufferedWriter bw2 = new BufferedWriter(fw2);
PrintWriter pw1 = new PrintWriter(bw1);
PrintWriter pw2 = new PrintWriter(bw2);
pw1.print("STUDENT ID\t"+"SUBJECT CODE\t"+"CARRY MARK\t"+"STATUS\t"+"FINAL EXAM\t"+"STATUS\t"+"TOTAL MARK\t"+"STATUS\t"+"GRADE\t"+"GRADE SCORE");
pw1.println();
pw2.print("STUDENT ID\t"+"SUBJECT CODE\t"+"CARRY MARK\t"+"STATUS\t"+"FINAL EXAM\t"+"STATUS\t"+"TOTAL MARK\t"+"STATUS\t"+"GRADE\t"+"GRADE SCORE");
pw2.println();
int index=0;
Assessment [] a = new Assessment[100];
Assessment [] b = new Assessment[100];
double[] CM=new double[100]; //array for CarryMark
double[] FM= new double[100]; //array for FullMark
boolean[] PG=new boolean[100]; //array for Passing-Grade
while(((inData=br.readLine()) !=null))
{
StringTokenizer st = new StringTokenizer(inData,"#");
StudName=st.nextToken();
StudID=st.nextToken();
SubName=st.nextToken();
FullOn=Integer.parseInt(st.nextToken());
FullEX=Integer.parseInt(st.nextToken());
mark=Double.parseDouble(st.nextToken());
fullM=Integer.parseInt(st.nextToken());
EMark=Double.parseDouble(st.nextToken());
fullEM=Integer.parseInt(st.nextToken());
a[index]=new Ongoing_Assessment(StudName, StudID, SubName,FullOn, FullEX, mark, fullM);
b[index]=new Final_Exam_Assessment(StudName, StudID, SubName,FullOn,FullEX,EMark, fullEM);
if(a[index] instanceof Ongoing_Assessment)
{
Ongoing_Assessment OA=(Ongoing_Assessment) a[index];
CM[index]=OA.getFinalMark();
}
if(b[index] instanceof Final_Exam_Assessment)
{
Final_Exam_Assessment FEA=(Final_Exam_Assessment) b[index];
FM[index]=FEA.getFinalMark();
}
if((CM[index]+FM[index])>=a[index].PassingGrade())
{
PG[index]=true;
}
else
{
PG[index]=false;
}
index++;
}
for(int i=0;i<index;i++)
{
String mss=" ";
String mss1=" ";
String mss2=" ";
String grade=" ";
double grade2=0.00;
if(PG[i])
{
mss="PASS";
}
else
{
mss="FAIL";
}
if(a[i] instanceof Ongoing_Assessment)
{
Ongoing_Assessment OA=(Ongoing_Assessment) a[i];
mss1=OA.toString();
}
if(b[i] instanceof Final_Exam_Assessment)
{
Final_Exam_Assessment FEA=(Final_Exam_Assessment) b[i];
mss2=FEA.toString();
}
if(mss.equals("PASS"))
{
if((CM[i]+FM[i])>=91 &&(CM[i]+FM[i])<=100)
{
grade="A+";
grade2=4.00;
}
else if((CM[i]+FM[i])>=80 &&(CM[i]+FM[i])<=90)
{
grade="A";
grade2=4.00;
}
else if((CM[i]+FM[i])>=75 &&(CM[i]+FM[i])<=79)
{
grade="A-";
grade2=3.67;
}
else if((CM[i]+FM[i])>=70 &&(CM[i]+FM[i])<=74)
{
grade="B+";
grade2=3.33;
}
else if((CM[i]+FM[i])>=65 &&(CM[i]+FM[i])<=69)
{
grade="B";
grade2=3.00;
}
else if((CM[i]+FM[i])>=60 &&(CM[i]+FM[i])<=64)
{
grade="B-";
grade2=2.67;
}
else if((CM[i]+FM[i])>=55 &&(CM[i]+FM[i])<=59)
{
grade="C+";
grade2=2.33;
}
else if((CM[i]+FM[i])>=50 &&(CM[i]+FM[i])<=54)
{
grade="C";
grade2=2.00;
}
}
else if(mss.equals("FAIL"))
{
if((CM[i]+FM[i])>=47 &&(CM[i]+FM[i])<=49)
{
grade="C-";
grade2=1.67;
}
else if((CM[i]+FM[i])>=44 &&(CM[i]+FM[i])<=46)
{
grade="D+";
grade2=1.33;
}
else if((CM[i]+FM[i])>=40 &&(CM[i]+FM[i])<=43)
{
grade="D";
grade2=1.00;
}
else if((CM[i]+FM[i])>=30 &&(CM[i]+FM[i])<=39)
{
grade="E";
grade2=0.67;
}
else if((CM[i]+FM[i])>=0 &&(CM[i]+FM[i])<=29)
{
grade="F";
grade2=0.00;
}
}
if(mss.equals("PASS"))
{
**strong text**pw1.print(mss1+mss2+"\t"+df.format((CM[i]+FM[i]))+"%\t\t"+mss+"\t"+grade+"\t"+df.format(grade2));
pw1.println();
}
else
{
pw2.print(mss1+mss2+"\t"+df.format((CM[i]+FM[i]))+"%"+mss+"\t"+grade+"\t"+df.format(grade2));
pw2.println();
}
}
br.close();
pw1.close();
pw2.close();
}