Why to add a Empty String while adding an string with int?

Question

In the below when I wasn't adding the ""(Empty String), the output was in int, which is pretty abnormal because adding a String with an int always gives a string. But as soon as I added the Empty String thing, the code seemed to work fine. In both the cases,I was adding a string from the string array that I created earlier in the code.

import java.io.*;

public class TooLong{
    public static void main(String[] args)  throws IOException{
        InputStreamReader n = new InputStreamReader(System.in);
        BufferedReader input = new BufferedReader(n);
        byte i ;
        i=Byte.parseByte(input.readLine());
        String origWords[] = new String[i];
        for (int j=0;j<i;j++)   origWords[j]= input.readLine();
        for (int j=0;j<i;j++){

            int charLength = origWords[j].length(); 
            if (charLength < 11)    System.out.println(origWords[j]);
            else System.out.println(origWords[j].charAt(0) +""+ (charLength-2) + origWords[j].charAt(charLength-1) );
        }
    }
}

Because `charAt(int index)` > Returns the char value at the specified index. — sleepToken, Jan 13 '20 at 14:16
Can you show us some examples? I don't think I understand what you want to say. — KunLun, Jan 13 '20 at 14:16
`charAt()` return `char` (basically a number) the `+` is define as `number + number`, cause `char` only contains one char, once you introduce `String` (`""`) the `+` became concatenation of strings — shahaf, Jan 13 '20 at 14:17

Jan · Accepted Answer · 2020-01-13T14:35:53.880

4

I assume, you are trying to achieve “internationalization ⇒ i18n”

That is because String.charAt(int) returns char. Which will be treated as numerical when using +. By using + with the empty String you force the compiler to convert everything to String

You can use String.substring(0,1) instead of the first charAt to force type String conversion

edited Jan 13 '20 at 14:35

answered Jan 13 '20 at 14:19

Jan

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Got it, one more question on which I am not able to get a short answer is, Scannner or Buffered Reader? – Satyam Bansal Jan 13 '20 at 14:23
2

:D https://stackoverflow.com/questions/2231369/scanner-vs-bufferedreader. My first google hit on “java Scanner or BufferedReader” – Jan Jan 13 '20 at 14:28

score 1 · Answer 2 · answered Jan 13 '20 at 14:53

The charAt() method of String returns the char. char is one of the primitive data types. char is a textual primitive, however, it also can do arithmetic operations like numerical primitives. The codes below are examples for it:

 `public static void main(String args[]){
            String st = "i am a string";
            char c = st.charAt(0);
            System.out.println(c);
            System.out.println(c+ st.charAt(2));
            System.out.println(c+ "" + st.charAt(2));
        }

`

The result of the above code will be:

 i
202
ia

Hope this example makes it clear.

Why to add a Empty String while adding an string with int?

2 Answers2