java program to count numbers in a file.

Question:

Design and implement a program that counts the number of integer values in a text input file.

Code:

import java.util.*;
import java.io.*;
 
public class CountNumbers {
  public static void main(String[] args) {
    try {
      File f = new File("numbers.txt");
      Scanner scanner = new Scanner(f);
      int total = 0;
      System.out.println("Numbers:");
      while(scanner.hasNext()) {
        String str = scanner.next();
        if(isInteger(str)){
          System.out.println(str);
          total++;
        }
      }
      System.out.println("Total: " + total);
    } catch(Exception e) {
    }
  }
 
  public static boolean isInteger(String input) {
    try {
      Integer.parseInt(input);
      return true;
    } catch (NumberFormatException e) {
      return false;
    }
  }
}

Output:

$ java CountNumbers
Numbers:
1
2
3
4
5
6
7
8
9
Total: 9


$ cat numbers.txt 
1 2 3 word 4 5 word 
6 word 7 word 
word word word 8  word word  
string string
This is a test
9 
the end