Java System.out.println after reading from HashMap

Question

The following is my code:

public void serialize() throws IOException {
    if(this.DO.size()==0){
        return;
    }
    for(Map.Entry<SearchKey,Float>set:DO.entrySet()){
        SearchKey key = set.getKey();
        float dist = set.getValue();
        long code = key.mc;
        char level = key.level;
        System.out.println(code);
        System.out.println(level);
        System.out.println(dist);
    }

}

The dataset has 4 elements:

274672398340,10,561.53235
1125058143634206,13,68.06594
1125058143634189,13,18.427612
1125058143634204,13,86.49355

where the first entry is the key and the middle entry is the level and the last entry is the distance. When I used Intelijj debugger, I found code, level and dist actually have the right values, but when I use the print statement, I got the following:

274672398340


561.53235
1125058143634206

68.06594
1125058143634189

18.427612
1125058143634204

86.49355

Does anyone know what may cause this error? Thanks.

What output do you expect? And why isn't each number on a separate line? Are you running the code in your question? — tgdavies
– tgdavies, Commented Jul 13, 2022 at 22:21
By the way, let me remind you that char/Character has been legacy since Java 5, essentially broken since Java 2. As a 16-bit type, char is physically incapable of representing most characters. I suggest defining your field with a different data type. — Basil Bourque
– Basil Bourque, Commented Jul 13, 2022 at 22:37
Hello thank you. Yes I ran the code. It was supposed to print out a total of 12 numbers each at a separate line. But here some numbers are missing. I feel the answer below helps. Also thank you Basil for this reminder. I actually did not know that. — libinzhou
– libinzhou, Commented Jul 14, 2022 at 1:32

majusebetter · Accepted Answer · 2022-07-13 22:29:03Z

1

The problem is char level = key.level;.

Since you have a char data type, System.out.println() prints a character instead of a number, i.e. the number is interpreted as ASCII code. ASCII code 10 is LINE FEED, code 13 is CARRIAGE RETURN - that's why you see those newlines.

Try to cast the char to int when printing:

System.out.print((int) level);

This should do the trick.

answered Jul 13, 2022 at 22:29

majusebetter

1,6021 gold badge6 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Basil Bourque Over a year ago

Good catch, and a good Answer. An even better solution might be avoiding the use of the char as the type of key.level.

libinzhou Over a year ago

Thank you! The problem is solved. And I will try to switch to short now. I was too greedy to try to save this 1 byte between char and short because I know my level is at most 20.

Collectives™ on Stack Overflow

Java System.out.println after reading from HashMap

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related