Difference between char (int) and int

Question

I have a piece of code, that receives values from a sensor (Via serialport using rxtx) and displays it. Strangely, the following code

int value = in.read();
System.out.print((char) value);

Outputs the desired value as:

RXTX Warning:  Removing stale lock file. /var/lock/LK.005.018.009
20
27
29
26
21

But when I change the above code as following:

int value = in.read();
System.out.print("The value is"+(char) value);

The output becomes:

RXTX Warning:  Removing stale lock file. /var/lock/LK.005.018.009
The value is2The value is6The value is
The value is2The value is2The value is

As it can be seen, the integer splits. For quite a while, I am unable to figure it out?

Is there a way where I can save the console value into an integer, as I would be using this value in the future.

Loose the `(char)` cast. – Anders R. Bystrup Jan 08 '13 at 10:11 — Anders R. Bystrup, Jan 08 '13 at 10:11

score 2 · Accepted Answer · edited Jan 25 '20 at 16:37

2

As it can be seen, the integer splits. For quite a while, I am unable to figure it out?

You are not reading integers, you are reading bytes which have characters encoded as ?ASCII?

Is there a way where I can save the console value into an integer, as I would be using this value in the future?

The simplest way is to use a Scanner

Scanner scanner = new Scanner(in);
while (scanner.hasNextInt()) {
   // read bytes up the next whitespace, parse as a int
   int n = scanner.nextInt();

edited Jan 25 '20 at 16:37

Dharman

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answered Jan 08 '13 at 10:14

Peter Lawrey

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I tried using the scanner. I tried incorporating the above code of yours as follow: `while (scanner.hasNextInt()) { // read bytes up the next whitespace, parse as a int int n = scanner.nextInt(); System.out.println("integer value is"+n); }` And the output I get is :`2integer value is1 1integer value is9` – Spaniard89 Jan 08 '13 at 10:18
1

Thanks a lot, it was helpful. I tried some modification in your code. And got it working. – Spaniard89 Jan 08 '13 at 10:56
Why do you get a number before the word "integer"? – Peter Lawrey Jan 08 '13 at 10:56
I have programmed my sensor in a way that, it would send the value every 10 sec. And I think the sensor tramsits the value one by one. In the above output 1 is transmitted first and 9 again. And it is displayed as 19 on the output screen. So in the above code, scanner is called immediately once a number is transmitted. I tried calling the scanner part every 5sec. So now it works like charm :) – Spaniard89 Jan 08 '13 at 11:02

score 0 · Answer 2 · answered Jan 08 '13 at 10:10

0

Don't cast it to char. Just print

System.out.print("The value is " + value);

answered Jan 08 '13 at 10:10

Zoltán

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I tried it, but when I do that, I get some random undesired value. I have programmed my sensor in such a way that, every 10 sec it would transmit the light value. But when I just print it out as it is, For every 10 sec I get more than 4-5 values like this : `The value is50The value is51The value is10The value is50` – Spaniard89 Jan 08 '13 at 10:14

score 0 · Answer 3 · answered Jan 08 '13 at 10:14

0

In second example you are converting int to char, but when you concatenate it to string you don't see anything because these are non printable characters.

answered Jan 08 '13 at 10:14

partlov

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score 0 · Answer 4 · answered Jan 08 '13 at 10:16

0

Your code converted the value number into a character, using Java's UCS2 representation. You may need it only if you want to treat the value as a character data (e.g. String).

If you need it only as an integer value (e.g. for printing), you don't need to convert.

answered Jan 08 '13 at 10:16

gaborsch

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I tried not casting it into char, but I don't get the appropriate output. – Spaniard89 Jan 08 '13 at 10:21
OK, I can see from the accepted answer that your main problem was how to READ data from the input channel. This way the title for the topic is a bit misleading. – gaborsch Jan 09 '13 at 08:58

score 0 · Answer 5 · answered Jan 08 '13 at 11:39

please check this snippet by adopting to your code

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));   
   String  line = br.readLine();
   String[] words = line.split("[ ]",0); //white space delimiter
   for(int i = 0; i < words.length; i++) {
   System.out.print("The value is " +words[i]);
   System.out.print("\n");

Difference between char (int) and int

5 Answers5