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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