Programming Tutorials

Question: Find the right solution based on the provide code.

By: Ash  

1. FileOutputStream fos = new FileOutputStream("datafile");
2. DataOutputstream dos = new DataOutputstream(fos); 3. for(int i=0; i<500; i++)
4. dos.writeInt(i);

You would like to write code to read back the data from this file. Which solutions listed below will work? (Choose none, some, or all).

A. Construct a FileInputStream, passing the name of the file. Onto the FileInputStream, chain a DataInputStream, and call its readInt() method.

B. Construct a FileReader, passing the name of the file. Call the file reader's readInt() method.

C. Construct a PipedInputStream, passing the name of the file. Call the piped input stream's readInt() method.

D. Construct a RandomAccessFile, passing the name of the file. Call the random access file's readInt() method.

E. Construct a FileReader, passing the name of the file. Onto the FileReader, chain a DataInputStream, and call its readInt() method.

Answer:A and D are correct. Solution A chains a data input stream onto a file input stream. Solution D simply uses the RandomAccessFile class. B fails because the FileReader class has no readInt() method; readers and writers only handle text. Solution C fails because the PipedInputStream class has nothing to do with file I/O. (Piped inout and output streams are used in inter-thread communication). Solution E fails because you cannot chain a data input stream onto a file reader. Readers read chars, and input streams handle bytes.

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