Formatting table - why does '\t' get changed?

Question

I want to format a grid nicely. It is 9x9 grid. I want to delimit it

after every 3rd column - put "*"

else - '\t'.

after every 3rd row put "-------------------------"

Horizontal line works nicely - this is easy.

But in column 3 it starts printing only 2-3 spaces instead of '\t'.

The code:

  static int grid[9][9] ;

void print_grid(){
     cout << "PRINTING GRID" <<endl ;
     for(int row = 0 ; row < 9 ; row++){
            for(int column = 0 ; column < 9 ; column++){
                    if(column > 0 && (column + 1) % 3 == 0 && (column + 1) != 9 )
                          cout <<grid[row][column] << " * " ;
             else    cout  <<grid[row][column]  <<"\t" ;                                                           
                    }
                    if( (row+1) % 3 == 0){cout <<endl ; 
                      cout << "---------------------------------------------------------------------" <<endl ;}
                    else  cout <<endl <<endl ;                    
            }

     }

int main(){
     print_grid() ;   
    return 0 ;         
    }

My question is: in the red area why does it print 2-3 spaces instead of "\t" ? why does '\t' change its length??

Answer 1

The tab key doesn't have a certain length, all it does is advanced the cursor to the next stop in the document.

The length of the distance between stops can vary from system to system.

Answer 2

You really don't want tab here you want to use iostream alignment manipulators.

Answer 3

Your code is fine. It's just the way tabs work in the console, they go to next tab stop which will be very 8 characters. If there are 5 characters already since last tab stop, it will only advance 3 characters.

You can check you get similar results by just using echo

echo -e "X\tX\nXXXXX\tX"
X       X
XXXXX   X

You can use two consecutive tabs if you want more space. If you want more control on alignment than that, you can stop using tabs and try using std::setw instead.