How to use hasNext () in java

This article mainly introduces how to use hasNext () in java, which has a certain reference value. Interested friends can refer to it. I hope you will gain a lot after reading this article.

Write a program to output the sum of numbers and "attention" characters if you enter a set of numbers that contain non-integer numbers, and output the sum of numbers if they are all numbers.

Program 1:

Package mian;import java.util.Scanner;public class mian {public static void main (String [] args) {/ / TODO Auto-generated method stub Scanner sc = new Scanner (System.in); int sound0; String str=null; while (sc.hasNext ()) {if (sc.hasNextInt ()) {/ / determine whether it is a digital s+=sc.nextInt ();} else {str=sc.next () / / not writing this sentence will cause only the sum of non-numeric numbers to be added, and the non-numeric string must be absorbed}} System.out.println (s); if (stringed numbers null) {System.out.println ("attention");} sc.close ();}}

Program 2:

Import java.util.Scanner;public class Main {/ / return-1:-10 (with a minus sign) / / return 1: + 10 (with a plus sign) / / return 0 non-numeric string / / return 2: 10 (without a sign) public static int checkNum (String str) {/ / determine whether it is a numeric string if (str.charAt (0) = ='-') {for (int istring 1 + i9 | | str.charAt (I) -'0')