Java Scanner nextInt() Method

---

---

Description

The java Scanner nextInt() method Scans the next token of the input as an int.An invocation of this method of the form nextInt() behaves in exactly the same way as the invocation nextInt(radix), where radix is the default radix of this scanner.

Declaration

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

public int nextInt()

Parameters

NA

Return Value

This method returns the int scanned from the input

Exception

• InputMismatchException − if the next token does not match the Integer regular expression, or is out of range

• NoSuchElementException − if the input is exhausted

• IllegalStateException − if this scanner is closed

Java Scanner nextInt(int radix) Method

Description

The java.util.Scanner.nextInt(int radix) method scans the next token of the input as an int. This method will throw InputMismatchException if the next token cannot be translated into a valid int value as described below. If the translation is successful, the scanner advances past the input that matched.

Declaration

Following is the declaration for java.util.Scanner.nextInt(int radix) method

public int nextInt(int radix)

Parameters

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

Return Value

This method returns the int scanned from the input

Exception

• InputMismatchException − if the next token does not match the Integer regular expression, or is out of range

• NoSuchElementException − if the input is exhausted

• IllegalStateException − if this scanner is closed

Getting Next Token as Int of a Scanner on a String Example

The following example shows the usage of Java Scanner nextInt() method to scan the next token as Int with default radix. We've created a scanner object using a given string. Then we checked each token to be Int and printed otherwise Not Found is printed along with scanned token. 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 a Int
         if(scanner.hasNextInt()){
            // print what is scanned
            System.out.println("Found: " + scanner.nextInt());		 
         } else {
            System.out.println("Not Found: " + scanner.next());
         }
      }

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

Output

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

Not Found: Hello
Not Found: World!
Found: 3
Not Found: +
Not Found: 3.0
Not Found: =
Found: 6

Getting Next Token as Int with Radix of a Scanner on a String Example

The following example shows the usage of Java Scanner nextInt() method to scan the next token as Int with given radix. We've created a scanner object using a given string. Then we checked each token to be Int and printed otherwise Not Found is printed along with scanned token. 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 a Int
         if(scanner.hasNextInt(4)){
            // print what is scanned
            System.out.println("Found: " + scanner.nextInt(4));		 
         } else {
            System.out.println("Not Found: " + scanner.next());
         }
      }

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

Output

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

Not Found: Hello
Not Found: World!
Found: 3
Not Found: +
Not Found: 3.0
Not Found: =
Not Found: 6

Getting Next Token as Int of a Scanner on User Input Example

The following example shows the usage of Java Scanner nextInt() method to scan the next token as Int with given radix. We've created a scanner object using System.in class. Then we checked each token to be Int and printed otherwise Not Found is printed along with scanned token. 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(4)){
         // print what is scanned
         System.out.println("Found: " + scanner.nextInt(4));		 
      } else {
         System.out.println("Not Found: " + 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)

3
Found: 3