String concatenation is not working properly

Question

I have the following code:

public boolean prontoParaJogar() throws RemoteException { int i; int j; if (this.jogadores==2) { this.jogando=1; for (i=0;i<3;i++) for(j=0;j<3;j++) { this.tabuleiro[i][j]=0; } for (i=0;i<3;i++) { System.out.println("Linha "+i+": "); System.out.print(this.tabuleiro[i][0]+' '); System.out.print(this.tabuleiro[i][1]+' '); System.out.print(this.tabuleiro[i][2]); System.out.println(""); } return true; } else { return false; } } 

it prints the following output:

  Linha 0:
 32320
 Linha 1: 
 32320
 Linha 2: 
 32320
 Linha 0: 
 32320
 Linha 1: 
 32320
 Linha 2: 
 32320

This is not what I expected. This should be the following output:

  Linha 0:
 0 0 0
 Linha 1:
 0 0 0
 Linha 2:
 0 0 0

I can’t understand why it is not working as expected.

Answer 1

 this.tabuleiro[i][0]+' ' 

' ' is a space character that has an ascii value of 32 . Single quotes mean char not a String

 this.tabuleiro[i][0]+" " 

will concatenate a space.

Answer 2

because you add ' ' to your variables, since ' ' is a character with asci-code 32, it adds 32 to the zero value inside your array and prints 32. You need to write two fingerprints to have the output you formed on your own.

Answer 3

You add 0 + 32 because `` is a space and 32 ASCII, instead of doing string concatenation. Change to

 System.out.print(this.tabuleiro[i][0]+" "); 

Answer 4

In your output lines you use + ' ' . This adds the symbol '' (symbol value 32) to each tabuleiro entry. You need to use + " " .

Answer 5

Also do not do this:

 for (i=0;i<3;i++) for(j=0;j<3;j++) { this.tabuleiro[i][j]=0; } 

but rather it:

 for (i=0;i<3;i++) { for(j=0;j<3;j++) { this.tabuleiro[i][j]=0; } } 

or at some point in the future you can do this:

 for (i=0;i<3;i++) System.out.println("i=" + i); for(j=0;j<3;j++) { this.tabuleiro[i][j]=0; } 

and be surprised that the second cycle does not run three times.