Java Scanner nextInt() Method with Example

Scanner Class nextInt() method: Here, we are going to learn about the nextInt() method of Scanner Class with its syntax and example.
Submitted by Preeti Jain, on March 26, 2020

Scanner Class nextInt() method

Syntax:

    public int nextInt();
    public int nextInt(int rad);

nextInt() method is available in java.util package.
nextInt() method is used to read the next token of the input as an int value at the implicit radix (rad) of this Scanner.
nextInt(int rad) method is used to read the next token of the input as an int value at the explicit or given radix (rad) of this Scanner.
These methods may throw an exception at the time of representing input as an int.
- InputMismatchException: This exception may throw when the next token of the input mismatch.
- NoSuchElementException: This exception may throw when no such element exists.
- IllegalStateException: This exception may throw when this Scanner is not opened.
These are non-static methods, it is accessible with class object & if we try to access these methods with the class name then we will get an error.

Parameter(s):

In the first case, nextInt(),
- It does not accept any parameter.
In the second case, nextInt(int rad),
- int rad – represents the radix used to manipulate the token as an int.

Return value:

In both the cases, the return type of the method is int, it retrieves the int read from the input.

Example 1:

// Java program is to demonstrate the example
// of nextInt() of Scanner

import java.util.*;
import java.util.regex.*;

public class NextInt {
 public static void main(String[] args) {
  String str = "Java Programming! 3 * 8= 24 + b";
  byte b = 10;

  // Instantiates Scanner
  Scanner sc = new Scanner(str);

  while (sc.hasNext()) {
   // By using nextInt() method isto
   // return the next token as a 
   // int in the default radix
   if (sc.hasNextInt()) {
    int next_i = sc.nextInt();
    System.out.println("sc.nextInt()): " + next_i);
   }
   System.out.println(sc.next());
  }
  // Scanner closed
  sc.close();
 }
}

Output

Java
Programming!
sc.nextInt()): 3
*
8=
sc.nextInt()): 24
+
b

Example 2:

import java.util.*;
import java.util.regex.*;

public class NextInt {
 public static void main(String[] args) {
  String str = "Java Programming! 3 * 8= 24 + b";
  byte b = 10;

  // Instantiates Scanner
  Scanner sc = new Scanner(str);

  while (sc.hasNext()) {
   // By using nextInt(9) method isto
   // return the next token as a 
   // int in the given radix
   if (sc.hasNextInt()) {
    int next_i = sc.nextInt(9);
    System.out.println("sc.nextInt(9)): " + next_i);
   }
   System.out.println(sc.next());
  }
  // Scanner closed
  sc.close();
 }
}

Output

Java
Programming!
sc.nextInt(9)): 3
*
8=
sc.nextInt(9)): 22
+
b

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