CODEWITHSUNDEEP
clinuxprintfcoordinate-systems
good5dog5
good5dog5

Reputation: 149

gotoxy() function using printf() 's position

Hello there
i am working a project which need the gotoxy() function
i have read gotoxy() implementation for Linux using printf

i wonder why the

void gotoxy(int x,int y)
{
    printf("%c[%d;%df",0x1B,y,x);
}

need to change the x y order in printf, is that just to fit the coordinate system?
in my way, i change it to printf("%c[%d;%df",0x1B,x,y) to meet my needs

stil, during my using this gotoxy() in for loop like this:

for( int i = 0; i < 12; i++ ) {
        for( int j = 0; j < 12; j++ ) {
            gotoxy( i , j );
            usleep(500000);
        }
    }

when i = 0 and i = 0, the cursor are on the first row
i wonder why cursor does't go to second row when i = 1?

Upvotes: 3

Views: 19631

Answers (5)

Pike
Pike

Reputation: 1

The above C code worked after I converted to Android script (I think I'm using Korn Shell).

function gotoxy()
{
printf "\033[$1;$2f"
}

I've beenn using "\033[r;cH" all this time and it was working.

Upvotes: -1

Om Prakash Kumar
Om Prakash Kumar

Reputation: 51

GotoXY is a function or procedure that positions the cursor at (X,Y), X in horizontal, Y in vertical direction relative to the origin of the current window. The origin is located at (1,1), the upper-left corner of the window.

Upvotes: 0

chux
chux

Reputation: 153582

OP: "why the need to change the x y order".
The cursor position command's format is 

Force Cursor Position   <ESC>[{ROW};{COLUMN}f

The need arises because to match that format and have your y variable as the ROW, y comes first. (You could rotate your screen 90 degrees instead).

OP: why cursor does't go to second row when i = 1?
The home position, at the upper left of the screen is the Origin being line 1, column 1

Note: You can put the escape character in the format, 

printf("\x1B[%d;%df", y, x);
fflush(stdout);  // @jxh

Upvotes: 4

jxh
jxh

Reputation: 70422

The column and row positions do not start at 0 when using the terminal escape sequences. They start at 1.

You need to flush stdout to see the cursor move.

void gotoxy(int x,int y)
{
    printf("%c[%d;%df",0x1B,y,x);
    fflush(stdout);
}

Upvotes: 1

ash
ash

Reputation: 5155

The order of x and y matters because the names of the variables have no meaning to the operation of the gotoxy() function.

That function is outputing a terminal command sequence that moves to the specified coordinates. When the terminal sees that command sequence and processes it, y is expected first.

By the way, be careful with this solution as this is highly dependent on the type of terminal within which the program is run. In order to get wide terminal support with random movement and "drawing" on a terminal screen, ncurses or curses are your best bet. They are challenging to learn at first though.

Upvotes: 2

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