Saturday, April 16, 2011

JAVA Programming : Using Scanner for User Input

JAVA Scanner 

As we now know a little bit about Java programming we will start making our first program.  In this tutorial we learn how to get input from user. There are a number of ways for taking input form user in Java and one way is using Scanner. A Scanner class is already built in Java and present in the java.util package. A scanner takes input from various types of Input Streams.

Creating a Scanner Object:
Lets create a scanner object that accepts as input stream it means that scanner will take input from console. 

Scanner scan = new Scanner(;  // is an InputStream  

A scanner can take various types as input stream for example, here we have a File Reader as input stream that reads data from a file named as MyFile.

Scanner scanfile = new Scanner(new FileReader("MyFile"));           

Getting User Input form Console using Scanner : Lets create a class that take two integer input from user and prints their sum. To use the Scanner class, first we need to import it. Take a look at the code :

import java.util.Scanner;

public class UserInput {
  public static void main(String args[]){  
    int second ;
    int first;
    int total;
    Scanner scan = new Scanner(;

    System.out.println("enter 1st no.");
    first = scan.nextInt()//stores user input into first          

    System.out.println("enter 2nd no.");
    second = scan.nextInt()//stores user input into second

    total = first + second ;  //sum of first and second  
    System.out.println("sum = "+ total)

In the first line of code, we have an import statement to import Scanner class. Now we can use the Scanner class anywhere in our code. In our class we have three int variables first, second and total. Variable first and second will hold the user input and total will hold their sum.
To take integer input scanner has a method called nextInt. This methods reads the integer input by user. In the above code we have used this method two times and to save user input in int variables first and second.

Output of Program :

Note that if are using nextInt method and the input given is not integer, then compiler will give an error. There are some other methods that are used for different types of input.

int nextInt()
Reads the next input as an int. If the input is not an integer,InputMismatchException is thrown.
long nextLong()
Reads the next token as a long. If the next token is not an long,InputMismatchException is thrown.
float nextFloat()
Reads the next input as a float. If the input is not a float, InputMismatchException is thrown.
double nextDouble()
Reads the next input as a double. If the input is not a double, InputMismatchException is thrown.
String next()
Finds and returns the next complete token from this scanner and returns it as a string; a token is usually ended by whitespace such as a blank or line break.
String nextLine()
Reads the rest of the current line, excluding any line separator at the end.
void close()
Closes the scanner.


  1. This program is very good but it is not runing.
    it give error on "Scanner"

    1. dear:
      check application name it may be possible that the name of application is change and check all code
      line of import scanner ok thanks

  2. The program is fine, there is no error. If you are having some problem pls give details about error.

  3. it gives error always.plz help Scanner...

  4. i am having java1.4.2 this pgm dsnt run .plllzzzz help

  5. scanner was introduced in java 1.5, if you are using an older version of java use other class like BufferedReader, InputStream, DataInputStream.

    For example:

    BufferedReader reader = new BufferedReader(new InputStreamReader(;
    String input = reader.readLine();

  6. java case sensitive. use capital "S" for scanner

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