SYSTEM.IN.READ() IN JAVA

To read data from the user in java we have three techniques –

1. System.in.read()

2. Scanner

3. BufferedReader

System.in.read() – It is an abstract method which throws IOException. It reads next byte of data from the input stream. The value byte is returned as an int in the range of 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

It takes input as an character and print its ASCII value. Its main disadvantage is that it can take only one character at a time. And it only takes input as char and gives its ASCII code, to take other kind of input we have to cast it.

Example –

import java.io.IOException;

public class Read {

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

                   System.out.println("Enter a character i will remain same but print 1 char");

                   char a = (char) System.in.read();

                   System.out.println(a);

          }

}

Output –

Enter a character i will remain same

abc

a

Example –

import java.io.IOException;

public class Read {

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

                   //char b = System.in.read(); //cannot convert from int to char

                   System.out.println("Enter any character i will print its ASCII code");

                   int c = System.in.read();

                   System.out.println(c);

          }

}

Output –

Enter any character i will print its ASCII code

A

65