randomacc.java

刘艺编著的java教程的课本习题加例题代码 很有用哦！

import java.io.*;
public class RandomAcc{
  private int d;
  public void creat(RandomAccessFile rwf){
   int i,j,k,t;
   try{
   rwf.seek(0);
   for(i=1;i<=10;i++){
    d=(int)(Math.random()*100);
    if(i==1)
     rwf.writeInt(d);
    else{
     if(d>rwf.readInt()){
        rwf.seek((i-1)*4);
        rwf.writeInt(d);
     }
     else{
       for(j=1;j<=i-1;j++){
         rwf.seek((j-1)*4);
         if(d<rwf.readInt())break;
       }
       for(k=i-1;k>=j;k--){
          rwf.seek((k-1)*4);
          t=rwf.readInt();
          rwf.seek(k*4);
          rwf.writeInt(t);
       }
       rwf.seek((j-1)*4);
       rwf.writeInt(d);
     }
    }
    rwf.seek((i-1)*4);}
   }
   catch(EOFException e){}
   catch(IOException e){}
 }
 public void showdata(RandomAccessFile rwf){
  int i=0,d=0;
  try{
   rwf.seek(i*4);
   while(true){
    d=rwf.readInt();
    System.out.print(d+",");
    i++;
    rwf.seek(i*4);
   }
  }
  catch(EOFException e){}
  catch(IOException e){}
 }
 public static void main(String args[]){
  try{
   RandomAcc ra=new RandomAcc();
   RandomAccessFile rwf=new RandomAccessFile("d:\\datafile\\file3.dat","rw");
   ra.creat(rwf);
   ra.showdata(rwf);
   rwf.close();
  }
  catch(FileNotFoundException e){}
  catch(IOException e){}
 }
}