How to take input using BufferedReader in Java

Question

Can someone explain me the method of taking input by using BufferedReader in Java?

Answer 1

BufferedReader is used to decrease the time for taking input. Generally, we use the Scanner class.

BufferedReader inp = new BufferedReader (new InputStreamReader(System.in));
int T= Integer.parseInt(inp.readLine()); // for taking a number as an input 
String str = inp.readLine(); // for taking a string as an input

For the case of an integer, you can take only input per line.

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Answer 2

Reading User's Input using BufferedReader class:

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. Here’s an example:

BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Enter your name: ");
String name = reader.readLine();
System.out.println("Your name is: " + name);

In the above example, the readLine() method reads a line of text from the command line.

Answer 3

yupp i am explaining every thing ..

We take Buffered Reader because previously in " cmd line argument " have some drawback i.e

1. at run end user didn't know which type of value,what value,in which order we have to take value like this not get any information of input value at runtime ...so..we" BufferReader" introduce it is a class which is introduced by" SUN MICROSYSTEM"

now , so when you take" BufferReader "then it will show all details at runtime which is demerit in "cmd line argument".

and when you enter detail at cmd prompt after asking value then it will store in "BufferReader Object"

and after storing it will return value as string format which is also in cmd and we use wrapper class so that what Primitive data type you want you will get it.

and for reading given input we take readline()....now what its mean firstly only read() will take first byte of typed input and store so readline() will read complete line from starting to the time of pressing enter button so,,

its store in BufferReader object its that we have to create one object for storing

BufferReader br=new BufferReader(new InputStrearmReader(System.im));

br object variable will creates a variable space with default value.

and in pakage IO its available so InputStreamReader taken and it will store input value which is type by keyboard and pass to BufferReader object.

and "System.in" is taken because it will connection to keyboard so we passed.

okkk now , let we have to take a num from keyboard and show as output by using BufferReader nw see below.

object creation =  BufferReader br=new BufferReader(new InputStrearmReader(System.im));

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

                             int num = Integer.parseInt(br.readline();

now see algorithm how its working in background in simple layman method...

when you type lets 20  which taken inside is in string form "20" and when you press enter then the string value will pass through"system.in " type tunnel which is connected to  keyboard to BR(bufferreader ) object  and when it reach in BR Object then stores there and after that through br.readline(); it will read first store value and return from there in string form "20" and then "Integer.parseInt" convert it into Integer type and give output as 20 which you read on cmd output through Sopln(num).

I hove you understand thanks....for further help ask again and again

from Rohan

Answer 4

This is the Java classical method to take input, Introduced in JDK1.0. 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.

• The wrapping code is hard to remember.

Program:

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// Java program to demonstrate BufferedReader import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; public class Test  {     public static void main(String[] args) throws IOException      {         //Enter data using BufferReader         BufferedReader reader =                     new BufferedReader(new InputStreamReader(System.in));                   // Reading data using readLine         String name = reader.readLine();            // Printing the read line         System.out.println(name);             } }

Input:

Edureka

Output:

Edureka

Answer 5

The BufferedReader class of Java is used to read the stream of characters from the specified source (character-input stream). The constructor of this class accepts an InputStream object as a parameter.

This class provides a method known as readLine() which reads and returns the next line from the source and returns it in String format.

The BufferedReader class doesn’t provide any direct method to read an integer from the user you need to rely on the readLine() method to read integers too. i.e. Initially you need to read the integers in string format.

The parseInt() method of the Integer class accepts a String value, parses it as a signed decimal integer and returns it.

Using this convert the read Sting value into integer and use. In short, to read integer value-form user using BufferedReader class −

• Instantiate an InputStreamReader class bypassing your InputStream object as a parameter.

• Then, create a BufferedReader, bypassing the above obtained InputStreamReader object as a parameter.

• Now, read integer value from the current reader as String using the readLine() method.

• Then parse the read String into an integer using the parseInt() method of the Integer class.

Example

The following Java program demonstrates how to read integer data from the user using the BufferedReader class.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
class Employee{
   String name;
   int id;
   int age;
   Employee(String name, int age, int id){
      this.name = name;
      this.age = age;
      this.id = id;
   }
   public void displayDetails(){
      System.out.println("Name: "+this.name);
      System.out.println("Age: "+this.age);
      System.out.println("Id: "+this.id);
   }
}
public class ReadData {
   public static void main(String args[]) throws IOException {
      BufferedReader reader =new BufferedReader(new InputStreamReader(System.in));
      System.out.println("Enter your name: ");
      String name = reader.readLine();
      System.out.println("Enter your age: ");
      int age = Integer.parseInt(reader.readLine());
      System.out.println("Enter your Id: ");
      int id = Integer.parseInt(reader.readLine());
      Employee std = new Employee(name, age, id);
      std.displayDetails();
   }
}

Output

Enter your name:
Krishna
Enter your age:
25
Enter your Id:
1233
Name: Krishna
Age: 25
Id: 1233