Thread: reading a stream of numbers from standard input

guys, I'm trying to read a stream of numbers from standard input like: 2 3 -3 10 44 9 -1. The line ends once it read -1, but for some reason I have an endless loop... how could I read this stream of numbers one number at a time?

int num[] = new int[5];
        char ch;
 
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("enter series of number: ");         
        int i = 0;
         do{ 
             num[i] = bf.read();
             i++;                     
        }while(num[i] != -1);
 
         int j = 0;
         while(j < num.length) {
             System.out.println(num[j]);
             j++;
         }

you could println your variables each step of the way, and see what is going on...

Originally Posted by jps

you could println your variables each step of the way, and see what is going on...

I'm getting a bunch of strange numbers... I don't think I'm reading the correct input. At the same time I'm getting an outofboud exception. like I'm going beyond the 5 elements of the array

enter series of number: 
10 3 4 99 -1
49
48
32
51
32
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5
	at wordset.Stack.main(Stack.java:67)
Java Result: 1

Originally Posted by hackthisred

I'd recommend the following approach...

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
 
 
public class InputStuff {
 
	private List<Integer> getUserInput()
	{
		List<Integer> list = new ArrayList<Integer>();
		Scanner keyboard = new Scanner(System.in);
		while(keyboard.hasNext())
		{
			String input = keyboard.next();
			if(!input.equals("-1"))
				list.add(Integer.parseInt(input));
			else
				return list;
		}
		return list;
	}
 
	public static void main(String[] args)
	{
		for (Integer number  : new InputStuff().getUserInput()) 
		{
			System.out.print(number + " ");
		}
	}
}

Really? Your approach would be to make a dedicated instance method to invoke on an object that has no real purpose? You'd manually read a token using scanner.next() and *then* parse it as an integer? You'd compare the input to -1 via string equality rather than just comparing integers? You have two identical return statements when one could just be replaced by a break?

import java.util.List;
import java.util.ArrayList;
import java.util.Scanner;
 
public final class EchoSeries {
 
  private EchoSeries() { }
 
  static List<Integer> readSeries() {
    final Scanner scanner = new Scanner(System.in);
    final List<Integer> list = new ArrayList<Integer>();
    int n;
    while (scanner.hasNextInt() && (n = scanner.nextInt()) != -1) {
      list.add(n);
    }
    return list;
  }
 
  public static void main(String[] argv) {
    final List<Integer> series = readSeries();
    for (final int n : series) {
      System.out.println(n);
    }
  }
}

Static methods are bad? So Math.sin is bad, eh? I understand what you're trying to say, but this is clearly not enterprise scale... you appear to have to some degree a naive understanding of unit testing via mocking. Not trying to start a fight, just pointing out flaws in your code. You can choose to acknowledge them.