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
– sleepToken, Commented Jan 13, 2020 at 14:16
Can you show us some examples? I don't think I understand what you want to say. — KunLun
– KunLun, Commented Jan 13, 2020 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
– shahaf, Commented Jan 13, 2020 at 14:17

Jan · Accepted Answer · 2020-01-13 14:35:53Z

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, 2020 at 14:35

answered Jan 13, 2020 at 14:19

Jan

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2 Comments

Satyam Bansal Over a year ago

Got it, one more question on which I am not able to get a short answer is, Scannner or Buffered Reader?

Jan Over a year ago

:D stackoverflow.com/questions/2231369/scanner-vs-bufferedreader. My first google hit on “java Scanner or BufferedReader”

asymmetricat · Accepted Answer · 2020-01-13 14:53:47Z

1

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.

answered Jan 13, 2020 at 14:53

asymmetricat

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