Terminal control/Cursor movement

From Rosetta Code
Task
Terminal control/Cursor movement
You are encouraged to solve this task according to the task description, using any language you may know.
Task

Demonstrate how to achieve movement of the terminal cursor:

  • how to move the cursor one position to the left
  • how to move the cursor one position to the right
  • how to move the cursor up one line (without affecting its horizontal position)
  • how to move the cursor down one line (without affecting its horizontal position)
  • how to move the cursor to the beginning of the line
  • how to move the cursor to the end of the line
  • how to move the cursor to the top left corner of the screen
  • how to move the cursor to the bottom right corner of the screen


For the purpose of this task, it is not permitted to overwrite any characters or attributes on any part of the screen (so outputting a space is not a suitable solution to achieve a movement to the right).


Handling of out of bounds locomotion

This task has no specific requirements to trap or correct cursor movement beyond the terminal boundaries, so the implementer should decide what behavior fits best in terms of the chosen language.   Explanatory notes may be added to clarify how an out of bounds action would behave and the generation of error messages relating to an out of bounds cursor position is permitted.

AutoHotkey[edit]

DllCall("AllocConsole")
hConsole:=DllCall("GetConsoleWindow","UPtr")
Stdout:=FileOpen(DllCall("GetStdHandle", "int", -11, "ptr"), "h `n")
Stdin:=FileOpen(DllCall("GetStdHandle", "int", -10, "ptr"), "h `n")
 
;move the cursor one position to the left
GetPos(x,y)
SetPos(x-1)
 
;move the cursor one position to the right
GetPos(x,y)
SetPos(x+1)
 
;move the cursor up one line (without affecting its horizontal position)
GetPos(x,y)
SetPos(x,y-1)
 
;move the cursor down one line (without affecting its horizontal position)
GetPos(x,y)
SetPos(x,y+1)
 
;move the cursor to the beginning of the line
GetPos(x,y)
SetPos(0,y)
 
;move the cursor to the end of the line
;requires previous knowledge of screen width -- typically 80
SetPos(79) ;minus 1 because origin is (0,0)
 
;move the cursor to the top left corner of the screen
SetPos(0,0)
 
;move the cursor to the bottom right corner of the screen
GetConsoleSize(w,h)
SetPos(w-1,h-1) ;minus 1 because origin is (0,0)
 
GetPos(ByRef x, ByRef y) {
global Stdout
VarSetCapacity(struct,22,0)
e:=DllCall("GetConsoleScreenBufferInfo","UPtr",Stdout.__Handle,"Ptr",&struct)
if (!e) or (ErrorLevel)
return 0 ;Failure
x:=NumGet(&struct,4,"UShort")
y:=NumGet(&struct,6,"UShort")
return 1
}
 
SetPos(x="",y="") {
global Stdout
GetPos(ox,oy)
if x is not Integer
x:=ox
if y is not Integer
y:=oy
VarSetCapacity(struct,4,0)
Numput(x,struct,"UShort")
Numput(y,struct,2,"UShort")
e:=DllCall("SetConsoleCursorPosition","Ptr",Stdout.__Handle,"uint",Numget(struct,"uint"))
if (!e) or (ErrorLevel)
return 0 ;Failure
return 1
}
 
GetConsoleSize(ByRef bufferwidth, ByRef bufferheight) {
global Stdout
VarSetCapacity(struct,22,0)
x:=DllCall("GetConsoleScreenBufferInfo","UPtr",Stdout.__Handle,"Ptr",&struct)
if (!x) or (ErrorLevel)
return 0 ;Failure
bufferwidth:=NumGet(&struct,"UShort")
bufferheight:=NumGet(&struct,2,"UShort")
return 1
}

Axe[edit]

Axe does not allow relative movement of the cursor. However, if the current position is known in the X and Y variables, the behavior can be simulated.

Output(X-1,Y)
Output(X+1,Y)
Output(X,Y-1)
Output(X,Y+1)
Output(0,Y)
Output(15,Y)
Output(0,0)
Output(15,7)

BASIC[edit]

Works with: GW-BASIC
Works with: QBasic
10 'move left
20 LOCATE , POS(0) - 1
30 'move right
40 LOCATE , POS(0) + 1
50 'move up
60 LOCATE CSRLIN - 1
70 'move down
80 LOCATE CSRLIN + 1
900 'beginning of line
100 LOCATE , 1
110 'end of line; requires previous knowledge of screen width -- typically 80
120 LOCATE , 80
130 'top left corner
140 LOCATE 1, 1
150 'bottom right corner; requires knowledge of screen dimensions (80x25 here)
160 LOCATE 25, 80

Applesoft BASIC[edit]

80-Column Text Card: Applesoft Control Codes http://support.apple.com/kb/TA33130

Apple II Family Identification http://www.umich.edu/~archive/apple2/technotes/tn/misc/TN.MISC.007

REM APPLE II GS ?
100 DATA56,32,31,254,160,0
110 DATA176,1,136,140,13,3,96
120 FOR I = 768 TO 780
130 READ B: POKE I,B
140 NEXT : CALL 768
150 IF PEEK (781) THEN 190
 
160 B = PEEK (64435) : T4 = 1
 
REM APPLE II ?
170 IF B = 56 THEN 200
 
REM APPLE II PLUS ?
180 IF B = 234 THEN 200
 
REM NOT 80 COLUMN MODE ?
190 T4 = PEEK (49183) < 128
 
REM START HERE
200 VTAB 12: HTAB 21
210 PRINT ">"; : UP = -998
 
REM LEFT
220 PRINT CHR$(8); : GET A$
 
REM RIGHT
230 IF T4 THEN CALL -1036
240 IF NOT T4 THEN PRINT CHR$(28);
250 GET A$
 
REM UP
260 CALL UP : GET A$
 
REM DOWN / LINE FEED
270 PRINT CHR$(10); : GET A$
 
REM BEGINNING OF LINE
300 HTAB 1 : ON T4 GOTO 350
310 IT = PEEK(37)
320 IF IT THEN CALL UP
330 PRINT
340 IF NOT IT THEN CALL UP
350 GET A$
 
REM END OF LINE
370 HTAB PEEK(33)
380 GET A$
 
REM TOP LEFT
400 IF T4 THEN VTAB 1 : HTAB 1
410 PRINT CHR$(25); : GET A$
 
REM BOTTOM RIGHT
420 CALL -1233
430 HTAB PEEK(33)
440 GET A$
 

BBC BASIC[edit]

      VDU 8    : REM Move one position to the left
VDU 9  : REM Move one position to the right
VDU 11  : REM Move up one line
VDU 10  : REM Move down one line
VDU 13  : REM Move to the beginning of the line
VDU 30  : REM Move to the top left corner
VDU 23,16,16;0;0;0; : REM Disable scrolling
VDU 13,8,10 : REM Move to the end of the line
VDU 30,8 : REM Move to the bottom right corner
VDU 23,16,0;0;0;0; : REM Enable scrolling

C[edit]

The conio.h header file in Borland's Turbo C makes keyboard interaction very simple. The following is an interactive program which has been tested with Turbo C, the delay function takes milliseconds and has been used to animate the involved cases.

 
/*Abhishek Ghosh, 7th November 2013, Rotterdam*/
#include<conio.h>
#include<dos.h>
 
char *strings[] = {"The cursor will move one position to the left",
"The cursor will move one position to the right",
"The cursor will move vetically up one line",
"The cursor will move vertically down one line",
"The cursor will move to the beginning of the line",
"The cursor will move to the end of the line",
"The cursor will move to the top left corner of the screen",
"The cursor will move to the bottom right corner of the screen"};
 
int main()
{
int i,j,MAXROW,MAXCOL;
struct text_info tInfo;
gettextinfo(&tInfo);
MAXROW = tInfo.screenheight;
MAXCOL = tInfo.screenwidth;
 
clrscr();
cprintf("This is a demonstration of cursor control using gotoxy(). Press any key to continue.");
getch();
 
for(i=0;i<8;i++)
{
clrscr();
gotoxy(5,MAXROW/2);
 
cprintf("%s",strings[i]);
getch();
 
switch(i){
case 0:gotoxy(wherex()-1,wherey());
break;
case 1:gotoxy(wherex()+1,wherey());
break;
case 2:gotoxy(wherex(),wherey()-1);
break;
case 3:gotoxy(wherex(),wherey()+1);
break;
case 4:for(j=0;j<strlen(strings[i]);j++){
gotoxy(wherex()-1,wherey());
delay(100);
}
break;
case 5:gotoxy(wherex()-strlen(strings[i]),wherey());
for(j=0;j<strlen(strings[i]);j++){
gotoxy(wherex()+1,wherey());
delay(100);
}
break;
case 6:while(wherex()!=1)
{
gotoxy(wherex()-1,wherey());
delay(100);
}
while(wherey()!=1)
{
gotoxy(wherex(),wherey()-1);
delay(100);
}
break;
case 7:while(wherex()!=MAXCOL)
{
gotoxy(wherex()+1,wherey());
delay(100);
}
while(wherey()!=MAXROW)
{
gotoxy(wherex(),wherey()+1);
delay(100);
}
break;
};
getch();
}
 
clrscr();
cprintf("End of demonstration.");
getch();
return 0;
}
 

C#[edit]

Works with: Mono version 1.2
Works with: Visual C# version 2003
static void Main(string[] args)
{
//There will be a 3 second pause between each cursor movement.
Console.Write("\n\n\n\n Cursor is here --> ");
System.Threading.Thread.Sleep(3000);
Console.CursorLeft = Console.CursorLeft - 1; //Console.CursorLeft += -1 is an alternative.
System.Threading.Thread.Sleep(3000);
Console.CursorLeft = Console.CursorLeft + 1;
System.Threading.Thread.Sleep(3000);
Console.CursorTop = Console.CursorTop - 1;
System.Threading.Thread.Sleep(3000);
Console.CursorTop = Console.CursorTop + 1;
System.Threading.Thread.Sleep(3000);
Console.CursorLeft = 0; //Move the cursor far left.
System.Threading.Thread.Sleep(3000);
Console.CursorLeft = Console.BufferWidth - 1;
/* BufferWidth represents the number of characters wide the console area is.
* The exact value may vary on different systems.
* As the cursor position is a 0 based index we must subtract 1 from buffer width or we move the cursor out of bounds.
* In some cases WindowWidth may be preferable (however in this demonstration window and buffer should be the same).
*/

System.Threading.Thread.Sleep(3000);
Console.SetCursorPosition(0,0); //I have used an alternative method for moving the cursor here which I feel is cleaner for the task at hand.
System.Threading.Thread.Sleep(3000);
Console.SetCursorPosition(Console.BufferWidth-1, Console.WindowHeight-1); //Buffer height is usually longer than the window so window has been used instead.
System.Threading.Thread.Sleep(3000);
}
 


Go[edit]

External commands[edit]

package main
 
import (
"fmt"
"time"
"os"
"os/exec"
"strconv"
)
 
func main() {
tput("clear") // clear screen
tput("cup", "6", "3") // an initial position
time.Sleep(1 * time.Second)
tput("cub1") // left
time.Sleep(1 * time.Second)
tput("cuf1") // right
time.Sleep(1 * time.Second)
tput("cuu1") // up
time.Sleep(1 * time.Second)
// cud1 seems broken for me. cud 1 works fine though.
tput("cud", "1") // down
time.Sleep(1 * time.Second)
tput("cr") // begining of line
time.Sleep(1 * time.Second)
// get screen size here
var h, w int
cmd := exec.Command("stty", "size")
cmd.Stdin = os.Stdin
d, _ := cmd.Output()
fmt.Sscan(string(d), &h, &w)
// end of line
tput("hpa", strconv.Itoa(w-1))
time.Sleep(2 * time.Second)
// top left
tput("home")
time.Sleep(2 * time.Second)
// bottom right
tput("cup", strconv.Itoa(h-1), strconv.Itoa(w-1))
time.Sleep(3 * time.Second)
}
 
func tput(args ...string) error {
cmd := exec.Command("tput", args...)
cmd.Stdout = os.Stdout
return cmd.Run()
}

ANSI escape codes[edit]

Not meeting all task requirements. Some of the movements are awkward with ANSI escape codes alone and are best done with one of the other techniques shown.

package main
 
import (
"fmt"
"time"
)
 
func main() {
fmt.Print("\033[2J\033[6;3H") // clear screen, move to an initial position
time.Sleep(1 * time.Second) // pause to let cursor blink
fmt.Print("\033[D") // left
time.Sleep(1 * time.Second)
fmt.Print("\033[C") // right
time.Sleep(1 * time.Second)
fmt.Print("\033[A") // up
time.Sleep(1 * time.Second)
fmt.Print("\033[B") // down
time.Sleep(1 * time.Second)
fmt.Print("\033[;H") // top left
time.Sleep(1 * time.Second)
}

Ncurses[edit]

Library: curses
package main
 
import (
"log"
"time"
 
gc "code.google.com/p/goncurses"
)
 
func main() {
s, err := gc.Init()
if err != nil {
log.Fatal("init:", err)
}
defer gc.End()
// an initial position
s.Move(6, 3)
s.Refresh() // update screen
time.Sleep(1 * time.Second) // allow time for cursor to blink
// left
y, x := s.CursorYX()
s.Move(y, x-1)
s.Refresh()
time.Sleep(1 * time.Second)
// right
y, x = s.CursorYX()
s.Move(y, x+1)
s.Refresh()
time.Sleep(1 * time.Second)
// up
y, x = s.CursorYX()
s.Move(y-1, x)
s.Refresh()
time.Sleep(1 * time.Second)
// down
y, x = s.CursorYX()
s.Move(y+1, x)
s.Refresh()
time.Sleep(1 * time.Second)
// beginning of line
y, x = s.CursorYX()
s.Move(y, 0)
s.Refresh()
time.Sleep(1 * time.Second)
// get window size for moves to edges
my, mx := s.MaxYX()
// end of line
y, x = s.CursorYX()
s.Move(y, mx-1)
s.Refresh()
time.Sleep(2 * time.Second)
// top left
s.Move(0, 0)
s.Refresh()
time.Sleep(2 * time.Second)
// bottom right
s.Move(my-1, mx-1)
s.Refresh()
s.GetChar()
}

Kotlin[edit]

Works with: Ubuntu version 14.04
// version 1.1.2
 
const val ESC = "\u001B" // escape code
 
fun main(args: Array<String>) {
print("$ESC[2J") // clear terminal first
print("$ESC[10;10H") // move cursor to (10, 10) say
val aecs = arrayOf(
"[1D", // left
"[1C", // right
"[1A", // up
"[1B", // down
"[9D", // line start
"[H", // top left
"[24;79H" // bottom right - assuming 80 x 24 terminal
)
for (aec in aecs) {
Thread.sleep(3000) // three second display between cursor movements
print("$ESC$aec")
}
Thread.sleep(3000)
println()
}

Lasso[edit]

#!/usr/bin/lasso9
 
local(esc = decode_base64('Gw=='))
 
stdoutnl('Demonstrate how to move the cursor one position to the left
Demonstrate how to move the cursor one position to the right
Demonstrate how to move the cursor up one line (without affecting its horizontal position)
Demonstrate how to move the cursor down one line (without affecting its horizontal position)
Demonstrate how to move the cursor to the beginning of the line
Demonstrate how to move the cursor to the end of the line
Demonstrate how to move the cursor to the top left corner of the screen
Demonstrate how to move the cursor to the bottom right corner of the screen
')
 
// place cursor in a suitable place before exercise
stdout(#esc + '[5;10H')
sleep(2000)
 
 
// move the cursor one position to the left
stdout(#esc + '[1D')
sleep(2000)
 
// move the cursor one position to the right
stdout(#esc + '[1C')
sleep(2000)
 
// move the cursor up one line
stdout(#esc + '[1A')
sleep(2000)
 
// move the cursor down one line
stdout(#esc + '[1B')
sleep(2000)
 
// move the cursor to the beginning of the line
stdout(#esc + '[100D')
sleep(2000)
 
// move the cursor to the top left corner of the screen
stdout(#esc + '[H')
sleep(2000)
 
// move the cursor to the bottom right corner of the screen
stdout(#esc + '[500;500H')
sleep(2000)

Mathematica[edit]

Run["tput cub1"]                  (* one position to the left *)
Run["tput cuf1" ] (* one position to the right *)
Run["tput cuu1" ] (* up one line *)
Run["tput cud1"] (* down one line *)
Run["tput cr"] (* beginning of line *)
Run["tput home"] (* top left corner *)
 
 
WIDTH=RunThrough["tput cols", ""];
HEIGHT=RunThrough["tput lines", ""];
 
Run["tput hpa "<>WIDTH] (* end of line *)
Run["tput cup "<>HEIGHT<>" "<> WIDTH] (* bottom right corner *)

Perl 6[edit]

shell "tput cub1";                  # one position to the left
shell "tput cuf1"; # one position to the right
shell "tput cuu1"; # up one line
shell "tput cud1"; # down one line
shell "tput cr"; # beginning of line
shell "tput home"; # top left corner
 
$_ = qx[stty -a </dev/tty 2>&1];
my $rows = +m/'rows ' <(\d+)>/;
my $cols = +m/'columns ' <(\d+)>/;
 
shell "tput hpa $cols"; # end of line
shell "tput cup $rows $cols"; # bottom right corner

PicoLisp[edit]

(call 'tput "cub1")                                # one position to the left
(call 'tput "cuf1") # one position to the right
(call 'tput "cuu1") # up one line
(call 'tput "cud1") # down one line
(call 'tput "cr") # beginning of the line
(call 'tput "hpa" (sys "COLUMNS")) # end of the line
(call 'tput "home") # top left corner
(call 'tput "cup" (sys "LINES") (sys "COLUMNS")) # bottom right corner


Python[edit]

Library: curses
import curses
 
scr = curses.initscr()
# Demonstrate how to move the cursor one position to the left
def move_left():
y,x = curses.getyx()
curses.move(y,x-1)
 
# Demonstrate how to move the cursor one position to the right
def move_right():
y,x = curses.getyx()
curses.move(y,x+1)
 
# Demonstrate how to move the cursor up one line (without affecting its horizontal position)
def move_up():
y,x = curses.getyx()
curses.move(y-1,x)
 
# Demonstrate how to move the cursor down one line (without affecting its horizontal position)
def move_down():
y,x = curses.getyx()
curses.move(y+1,x)
 
# Demonstrate how to move the cursor to the beginning of the line
def move_line_home()
y,x = curses.getyx()
curses.move(y,0)
 
# Demonstrate how to move the cursor to the end of the line
def move_line_end()
y,x = curses.getyx()
maxy,maxx = scr.getmaxyx()
curses.move(y,maxx)
 
# Demonstrate how to move the cursor to the top left corner of the screen
def move_page_home():
curses.move(0,0)
 
# Demonstrate how to move the cursor to the bottom right corner of the screen
def move_page_end():
y,x = scr.getmaxyx()
curses.move(y,x)
 

Racket[edit]

 
#lang racket
(require (planet neil/charterm:3:0))
(define x 0)
(define y 0)
 
(define (on-key k)
(match k
['down (move 0 -1)]
['up (move 0 +1)]
['right (move +1 0)]
['left (move -1 0)]
[else #f]))
 
(define (move dx dy)
(set! x (+ x dx))
(set! y (+ y dy))
(charterm-cursor x y))
 
(with-charterm
(charterm-clear-screen)
(charterm-cursor 0 0)
(let loop ([continue? #t])
(when continue?
(loop (on-key (charterm-read-key))))))
 


REXX[edit]

Works with: PC/REXX
Works with: Personal REXX

This version only works with PC/REXX or Personal REXX.

/*REXX pgm demonstrates how to achieve movement of the terminal cursor. */
 
parse value scrsize() with sd sw /*find the display screen size. */
parse value cursor() with row col /*find where the cursor is now. */
 
colL=col-1; if colL==0 then colL=sw /*prepare to move cursor to left.*/
call cursor row,colL /*move cursor to the left (wrap).*/
 
colR=col+1; if colR>sw then colL=1 /*prepare to move cursor to right*/
call cursor row,colR /*move cursor to the right (wrap)*/
 
rowU=row-1; if rowU==0 then rowU=sd /*prepare to move cursor up. */
call cursor rowU,col /*move cursor up (with wrap). */
 
rowD=row+1; if rowD>sd then rowD=1 /*prepare to move cursor down. */
call cursor rowD,col /*move cursor down (with wrap). */
 
call cursor row,1 /*move cursor to beginning of row*/
call cursor row,sw /*move cursor to end of row*/
call cursor 1,1 /*move cursor to top left corner.*/
call cursor sd,sw /*move cursor to bot right corner*/
 
/*stick a fork in it, we're done.*/

Tcl[edit]

Translation of: UNIX Shell
# Simplification wrapper for when we're actually affecting the terminal
proc tput args {
exec tput {*}$args >@stdout <@stdin
}
 
tput cub1; # one position to the left
tput cuf1; # one position to the right
tput cuu1; # up one line
tput cud1; # down one line
tput cr; # beginning of line
tput home; # top left corner
 
# For line ends and bottom, we need to determine size of terminal
set width [exec tput cols]
set height [exec tput lines]
 
tput hpa $width; # end of line
tput cpu $height $width; # bottom right corner

UNIX Shell[edit]

tput cub1                  # one position to the left
tput cuf1 # one position to the right
tput cuu1 # up one line
tput cud1 # down one line
tput cr # beginning of line
tput home # top left corner
 
# For line ends and bottom, we need to determine size
# of terminal
WIDTH=`tput cols`
HEIGHT=`tput lines`
 
tput hpa $WIDTH # end of line
tput cup $HEIGHT $WIDTH # bottom right corner

XPL0[edit]

include c:\cxpl\codes;  \intrinsic 'code' declarations
int I, X, Y, W, H;
[Cursor(10, 13); \set cursor to arbitrary location on screen
I:= ChIn(1); \wait for keystroke (no echo to display)
ChOut(0, $08\BS\); \backspace moves one position right
I:= ChIn(1);
X:= Peek($40, $50); \get cursor location from BIOS data
Y:= Peek($40, $51);
Cursor(X+1, Y); \move one position right
I:= ChIn(1);
Cursor(X+1, Y-1); \move up one line
I:= ChIn(1);
ChOut(0, $0A\LF\); \line feed moves down one line
I:= ChIn(1);
ChOut(0, $0D\CR\); \carriage return moves to beginning of current line
I:= ChIn(1);
W:= Peek($40, $4A); \get width of display (standard = 80; mine = 94)
Cursor(W-1, Y); \move to end of current line
I:= ChIn(1);
Cursor(0, 0); \move to top left corner
I:= ChIn(1);
H:= Peek($40, $84) + 1; \get height of display (standard = 25; mine = 50)
Cursor(W-1, H-1); \move to bottom right corner
I:= ChIn(1);
]

Moving the cursor position beyond the terminal boundaries simply makes the flashing cursor disappear. This is sometimes useful.

zkl[edit]

Translation of: Go

zkl doesn't know anything about terminals but can print Ansi terminal codes:

print("\e[2J\e[6;3H");	// clear screen, move to an initial position
Atomic.sleep(1); // pause to let cursor blink
print("\e[D"); // left
Atomic.sleep(1);
print("\e[C"); // right
Atomic.sleep(1);
print("\e[A"); // up
Atomic.sleep(1);
print("\e[B"); // down
Atomic.sleep(1);
print("\e[;H"); // top left
Atomic.sleep(1);

ZX Spectrum Basic[edit]

10 PRINT CHR$(8);:REM cursor one position left
20 PRINT CHR$(9);:REM cursor one position right
30 GO SUB 500: REM get cursor position
40 IF cr>0 THEN LET cr=cr-1: GO SUB 550: REM cursor up one line
50 IF cr<22 THEN LET cr=cr+1: GO SUB 550: REM cursor down one line
60 POKE 23688,33: REM cursor to beginning of the line
70 POKE 23688,0: REM cursor to end of line
80 POKE 23688,33:POKE 23689,24: REM cursor to top left
90 REM bottom two rows are reserved for input and errors
100 REM so we reserve those lines here
110 POKE 23688,0: POKE 23689,2: REM bottom right
 
499 STOP: REM do not overrun into subroutines
 
500 REM get cursor position
510 LET cc=33-PEEK 23688:REM current column
520 LET cr=24-PEEK 23689:REM current row
530 RETURN
 
550 REM set cursor position
560 PRINT AT cr,cc;
570 RETURN
 
600 REM alternative set cursor position
610 POKE 23688,33-cc
620 POKE 23689,24-cr
630 RETURN