Java IO Tutorial - Java PushbackReader.unread(char[] cbuf, int off, int len)

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Syntax

PushbackReader.unread(char[] cbuf, int off, int len) has the following syntax.

public void unread(char[] cbuf,  int off,  int len)  throws IOException

Example

In the following code shows how to use PushbackReader.unread(char[] cbuf, int off, int len) method.

//www .  java 2s  . co m

import java.io.*;

public class Main {

   public static void main(String[] args) {
      String s = "from java2s.com";

      StringReader sr = new StringReader(s);

      PushbackReader pr = new PushbackReader(sr, 20);

      try {
         for (int i = 0; i < 5; i++) {
            char c = (char) pr.read();
            System.out.println(c);
         }
         char cbuf[] = {'w', 'o', 'r', 'l', 'd'};

         pr.unread(cbuf, 1, 4);

         for (int i = 0; i < 4; i++) {
            char c = (char) pr.read();
            System.out.println(c);
         }

         pr.close();

      } catch (IOException ex) {
         ex.printStackTrace();
      }
   }
}

The code above generates the following result.

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