Java Scanner hasNextInt() Method

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Description

The Java Scanner hasNextInt() method returns true if the next token in this scanner's input can be interpreted as an int value in the default radix using the nextInt() method. The scanner does not advance past any input.

Declaration

Following is the declaration for java.util.Scanner.hasNextInt() method

public boolean hasNextInt()

Parameters

NA

Return Value

This method returns true if and only if this scanner's next token is a valid int value

Exception

IllegalStateException − if this scanner is closed

Java Scanner hasNextInt(int radix) Method

Description

The java.util.Scanner.hasNextInt(int radix) method returns true if the next token in this scanner's input can be interpreted as an int value in the specified radix using the nextInt() method. The scanner does not advance past any input.

Declaration

Following is the declaration for java.util.Scanner.hasNextInt() method

public boolean hasNextInt(int radix)

Parameters

radix − the radix used to interpret the token as an int value

Return Value

This method returns true if and only if this scanner's next token is a valid int value

Exception

IllegalStateException − if this scanner is closed

Checking Next Token as Int Using Scanner on a String Example

The following example shows the usage of Java Scanner hasNextInt() method to check if next token is a Int using a default radix. We've created a scanner object using a given string. Then we checked each token to be Int and printed. In the end scanner is closed using close() method.

package com.tutorialspoint;

import java.util.Scanner;

public class ScannerDemo {
   public static void main(String[] args) {

      String s = "Hello World! 3 + 3.0 = 6";

      // create a new scanner with the specified String Object
      Scanner scanner = new Scanner(s);

      while (scanner.hasNext()) {
         
         // check if the scanner's next token is an Int
         System.out.println("" + scanner.hasNextInt());

         // print what is scanned
         System.out.println("" + scanner.next());
      }

      // close the scanner
      scanner.close();
   }
}

Output

Let us compile and run the above program, this will produce the following result −

false
Hello
false
World!
true
3
false
+
false
3.0
false
=
true
6

Checking Next Token as Int with Radix 4 Using Scanner on a String Example

The following example shows the usage of Java Scanner hasNextInt() method to check if next token is a Int using a radix of 4. We've created a scanner object using a given string. Then we checked each token to be Int and printed. In the end scanner is closed using close() method.

package com.tutorialspoint;

import java.util.Scanner;

public class ScannerDemo {
   public static void main(String[] args) {

      String s = "Hello World! 3 + 3.0 = 6";

      // create a new scanner with the specified String Object
      Scanner scanner = new Scanner(s);

      while (scanner.hasNext()) {
         
         // check if the scanner's next token is an Int
         System.out.println("" + scanner.hasNextInt(4));

         // print what is scanned
         System.out.println("" + scanner.next());
      }

      // close the scanner
      scanner.close();
   }
}

Output

Let us compile and run the above program, this will produce the following result −

false
Hello
false
World!
true
3
false
+
false
3.0
false
=
false
6

Checking Next Token as Int Using Scanner on User Input Example

The following example shows the usage of Java Scanner hasNextInt() method to check if next token is a Int. We've created a scanner object using System.in class. Then we checked each token to be Int and printed. In the end scanner is closed using close() method.

package com.tutorialspoint;

import java.util.Scanner;

public class ScannerDemo {
   public static void main(String[] args) {

      // create a new scanner with System Input
      Scanner scanner = new Scanner(System.in);
         
      // check if the scanner's next token is a Int
      if(scanner.hasNextInt()){
         // print what is scanned
         System.out.println(scanner.next());		 
      } else {
         scanner.next();
      }

      // close the scanner
      scanner.close();
   }
}

Output

Let us compile and run the above program, this will produce the following result − (where we've entered 3.0.)

3
3