Taking Input from Users in Java | Scanner, BufferedReader, InputStream

In the following program, we will see data on how to take input from Users in Java using the following methods:

1. BufferedReader
2. Reading input data using Data InputStreamReader
3. Reading input data using Scanner

Also, you can use the Java compiler to compile a program.

1. Buffered Reader class.

This is the Java classical method to take input. This method is used by wrapping the System.in (standard input stream) in an InputStreamReader which is wrapped in a BufferedReader, we can read input from the user in the command line.

Advantages:

• The input is buffered for efficient reading.

Drawback:

• The wrapping code is hard to remember.

Java BufferedReader class Example

Roll number, name, salary take Input from Users.

SOURCE CODE:

import java.io.*;
class Rbuf
{
    public static void main(String args[]) throws IOException
 {
    int rollno;
    String name;
    float salary;
    
    BufferedReader s=new BufferedReader(new 
     InputStreamReader(System.in)); 
    //Create  object  
    
    System.out.println("Enter the Roll no:");
    rollno=Integer.parseInt(s.readLine()); //Input

    System.out.println("Enter the Name:");
    name=s.readLine(); //Input

    System.out.println("Enter the Salary:");
    salary=Float.parseFloat(s.readLine()); //Input

    System.out.println("Roll no:"+rollno);
    System.out.println("Name:"+name);
    System.out.println("Salary:"+salary);
 } //End of main
} //End of classimport java.io.*;

OUTPUT:
C:\A>javac Rbuf.java

C:\A>java Rbuf

Enter the Roll no:

59

Enter the Name:

SAM

Enter the Salary:

500

Roll no:59

Name:SAM

Salary:500.0

2. Data input Scream Class

Java DataInputStream class allows an application to read primitive data from the input stream in a machine-independent way. Java application generally uses the data output stream to write data that can later be read by a data input stream.

Data input Scream Class Example

Take roll number, name, salary from user as an input.

SOURCE CODE:

import java.io.*;
class Rdiss
{
    public static void main(String args[]) throws IOException
 {
    int rollno;
    String name;
    float salary;
    DataInputStream s=new DataInputStream(System.in); //Create 
    object
    
    System.out.println("Enter the Roll no:");
    rollno=Integer.parseInt(s.readLine()); //Input

    System.out.println("Enter the Name:");
    name=s.readLine(); //Input

    System.out.println("Enter the Salary:");
    salary=Float.parseFloat(s.readLine()); //Input

    System.out.println("Roll no:"+rollno);
    System.out.println("Name:"+name);
    System.out.println("Salary:"+salary);
 } //End of main
} //End of class

OUTPUT:

C:\A>javac Rdiss.java

C:\A>java Rdiss

Enter the Roll no:

01

Enter the Name:

SAM

Enter the Salary:500

Roll no:1

Name:SAM

Salary:500.0

3. Scanner class

The Scanner class is used to get user input, and it is found in the java.util package.

To use the Scanner class, create an object of the class and use any of the available methods found in the scanner class documentation. In our example, we will use the nextLine() method, which is used to read strings

Scanner class Class Example

Take roll number, name, salary from user as an input.

Source Code

import java.util.*;
class Rscanner
{
    public static void main(String args[]) 
    
 {
   int rollno;
   String name;
   float salary;
   Scanner s=new Scanner(System.in); //Create object
    
    System.out.println("Enter the Roll no:");
    rollno=s.nextInt(); //Input

    System.out.println("Enter the Name:");
     name=s.next(); //Input

    System.out.println("Enter the Salary:");
    salary=s.nextFloat(); //Input

    System.out.println("Roll no:"+rollno);
    System.out.println("Name:"+name);
    System.out.println("Salary:"+salary);
 } //END OF MAIN
} // END OF CLASS

OUTPUT.

C:\A>javac Rscanner.java

C:\A>java Rscanner

Enter the Roll no:

01

Enter the Name:

SAM

Enter the Salary:

500

Roll no:1

Name:SAM

Salary:500.0

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