USER INPUT USING BUFFERED READER IN JAVA

To work with BufferedReader class it provides a method readLine() to read input. It creates a buffering character-input stream that uses default-sized input buffer. Again in order to create an object of BufferedReader we have to create an object of InputStreamReader first. And in the argument of InputStreamReader we have to pass System.in.

Note – Whenever we work with any kind of IO operation it throws some kind of exception, so we should handle or suppress it.

Example –

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

public class BufferReader {

          public static void main(String[] args) throws IOException {

                   InputStreamReader isr = new InputStreamReader(System.in);

                   BufferedReader br = new BufferedReader(isr);

                   int i,j;

                   System.out.println("Enter i");

                   i=br.read();

                   System.out.println("Eneter j");

                   j=br.read();

                   System.out.println(i+j);

          }

}

Output –

Enter I       // 1

888

Eneter j

112

Enter I       // 2

88

Eneter j

112

Enter I       // 3

8

Eneter j

69

In the first output we enter 888 and simply the program exists without taking an input from user. As it takes input in form of byte here using read(). And it calculates the ASCII code of 8+8 = 56+56. In the second output also it is same. But in the third out even we enter 1 digit and press enter it gives out as 69 without taking input from user. Because it considers CR as the second input whose value is 13 i.e. the value of 8+CR = 56+13 i.e. 69.

Example –

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

public class BufferReader {

          public static void main(String[] args) throws IOException {

                   InputStreamReader isr = new InputStreamReader(System.in);

                   BufferedReader br = new BufferedReader(isr);

                   int i,j;

                   System.out.println("Enter i");

                   i=Integer.parseInt(br.readLine());

                   System.out.println("Enter j");

                   j=Integer.parseInt(br.readLine());

                   System.out.println(i+j);

          }

}

Output –

Enter i

5

Enter j

6

11

Note – After parsing the input as Integer and reading a line instead of character we fulfill our work.