Java Buzz Forum - How to read input from console in java using scanner

We are having special classes to take input from the user. One of the most commonly used class is java.util.Scanner.
We can read input from the console using scanner class.
Java.util.Scanner class provides lot of methods to take different typed of data from the user as input.
Scanner class is final class in java like String class.
Scanner class implements Iterator and Closeable interfaces.

Scanner class in Java

public final class Scanner
extends Object
implements Iterator<String>, Closeable

In order to read or take input from user we need to create object of Scanner class by using its constructor which takes System.in as an argument.
By using methods of System class we can take different type of data like string , int and float etc.
scannerObject.nextInt() will accepts integer value as an input .
scannerObject.nextLong() will accepts long value as an input from user.
We also take different type of data by using some delimiters
Using useDelimiter() method we can give data by using delimiters.
Lets see what are the different methods in java.util.scanner class.

Java.util.Scanner class methods:

Scanner class in java programming:

Program #1: Write a java example program to read integer type of data as an input from the user from console using scanner class

package com.scannerjava;
import java.util.Scanner;
public class TakeInputUsingScanner {
/**
* @wesite:www.instanceofJava.com
* @category: Java program to take input from user using scanner
*/
public static void main(String[] args) {
Scanner sc= new Scanner(System.in);
System.out.println("Please enter any integer value as input");
int x=sc.nextInt();
System.out.println("Entered integer value is "+x);
}
}

Output:

Please enter any integer value as input
33
Entered integer value is 33

Program #2: Write a java example program to read String type of data as an input from the user from console using scanner class

package com.scannerjava;
import java.util.Scanner;
public class TakeInputUsingScanner {
/**
* @wesite:www.instanceofJava.com
* @category: Java program to take input from user using scanner
*/
public static void main(String[] args) {
Scanner sc= new Scanner(System.in);
System.out.println("Please enter any Sting value as input");
String str=sc.next();
System.out.println("Entered String value is "+str);
}
}

Output:

Please enter any String value as input
instanceofjava
Entered String value is instanceofjava

Program #3: Write a java example program to read data as an input from the user from console using scanner class with delimiters

package com.scannerjava;
import java.util.Scanner;
public class TakeInputUsingScanner {
/**
* @wesite:www.instanceofJava.com
* @category: Java program to take input from user using scanner
*/
public static void main(String[] args) {
String input = "top 10 java interview questions on scanner class";
Scanner sc = new Scanner(input).useDelimiter("\\s");
System.out.println(sc.next());
System.out.println(sc.nextInt());
System.out.println(sc.next());
System.out.println(sc.next());
System.out.println(sc.next());
System.out.println(sc.next());
System.out.println(sc.next());
System.out.println(sc.next());
}
}

Output:

top
10
java
interview
questions
on
scanner
class

Program #4: Write a java example program to read all type of data as an input from the user from console using scanner class

package com.scannerjava;
import java.util.Scanner;
public class TakeInputUsingScanner {
/**
* @wesite:www.instanceofJava.com
* @category: Java program to take input from user using scanner
*/
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter an integer value");
System.out.println(sc.nextInt());
System.out.println("Enter a float value");
System.out.println(sc.nextFloat());
System.out.println("Enter a Double value");
System.out.println(sc.nextDouble());
System.out.println("Enter a Byte value");
System.out.println(sc.nextByte());
System.out.println("Enter a Long value");
System.out.println(sc.nextLong());
}
}

Output:

Enter an integer value
12
12
Enter a float value
12.34
12.34
Enter a Double value
12.3456789
12.3456789
Enter a Byte value
2
2
Enter a Long value
9876636363536
9876636363536

Program #5: Write a java example program how to read input from console in java eclipse all type of data as an input from the user from console using scanner class.


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