Thread: how to use arrows

how i use arrows in a program?



like -> to move right , <-- to move left etc...

??? what? ???


what i meaned is like:

[code/]
string x;

x = getch;

if ( x == "F" )
// do f;

else if ( x == "left arrow or smthing like that" )
//move left

[code]

see?

Originally Posted by wyvern

??? what? ???


what i meaned is like:

string x;

x = getch;

if ( x == "F" )
// do f;

else if ( x == "left arrow or smthing like that" )
//move left

see?

Sort out your CODE tags, and AFAIK that should be:

Code:

if (x == 'F')  // Not "F"
// etc...

Code:

#include <iostream>
#include <conio.h>

int main()
{
    int x=getch();
    while(x!=13)
    {
    std::cout<<x<<std::endl;
    x=getch();
    }
return 0;
}

That displays the value of x, which is what getchar returns. It quits when getchar returns 13, which is the enter key. Figure out what the arrow keys are.

Processing keyboard and mouse events is covered in part 5 of my console programming tutorial.

This is assuming you are using Windows of course, you were asked, but didn't answer.

I finnaly found a safe way to do it here it is

Code:

int x;

x = getch();

if ( x == 0x48 ) {}   // up

else if ( x == 0x4B ) {}  // left

else if ( x == 0x50){} // down

else if ( x == 0x 4D) {} // right

hope everyone finds this usefull as i also found it very usefull ^^

I wrote this recently, it should basically answer your question.

Code:

/* ******************************************
  Name: Detecting Extended Characters in DOS 
  Author: W----------------          ** Not a chance **
  Date: 06/10/05 12:43
  Description: Shows how a programmer may
  use functions in conio.h to detect extended 
  characters while still allowing the ability 
  to read non-extended characters.             
****************************************** */

#include <iostream.h>
#include <conio.h>    

const char UPKEY = 72;
const char LEFTKEY = 75;
const char RIGHTKEY = 77;
const char DOWNKEY = 80;
const char INSERTKEY = 82;
const char DELETEKEY = 83;
const char HOMEKEY = 71;
const char ENDKEY = 79;
const char PGUPKEY = 73;
const char PGDNKEY = 81;
const char SPACE = 32;
const char ENTER = 13;
const char TAB = 9;
const char BSPACE = 8;
const char ESC = 27;

int main() 
{
    bool isExtended;
    char keyPress;
    
    cout << "Press any key on your keyboard. This program should read" << endl
         << "and echo them all accordingly, with the exception of some" << endl
         << "certain keys, as they were either not defined or have" << endl 
         << "specific functions within the DOS window." << endl << endl;
    
    do
    {                  
    keyPress = getch();
    
    if (int(keyPress) == -32 || int(keyPress) == 0)  // Values returned by
    isExtended = true;                               // Extended Characters.
    else
    isExtended = false;
    
    cout << "You pressed ";
    
        if (isExtended == true)
        {           
           keyPress = getch();           // Reads in the second value of the 
                                         // Extended Character.          
           switch(keyPress)
             {
               case UPKEY:
               cout << "the UP key." << endl;
               break; 
               case DOWNKEY:
               cout << "the DOWN key." << endl;
               break;
               case LEFTKEY:
               cout << "the LEFT key." << endl;
               break;
               case RIGHTKEY:
               cout << "the RIGHT key." << endl;
               break;
               case INSERTKEY:
               cout << "the INSERT key." << endl;
               break;
               case DELETEKEY:
               cout << "the DELETE key." << endl;
               break;
               case HOMEKEY:
               cout << "the HOME key." << endl;
               break;
               case ENDKEY:
               cout << "the END key." << endl;
               break;
               case PGUPKEY:
               cout << "the PAGE UP key." << endl;
               break;
               case PGDNKEY:
               cout << "the PAGE DOWN key." << endl;
               break;
               default:
               cout << "an undefined extended character." << endl;
               break; 
             }
        }
        else if (isExtended == false)
        {
           switch(keyPress)
             {
               case SPACE:
               cout << "the SPACE key." << endl;
               break;
               case BSPACE:
               cout << "the BACKSPACE key." << endl;
               break;
               case ENTER:
               cout << "the ENTER key." << endl;
               break;
               case TAB:
               cout << "the TAB key." << endl;
               break;
               case ESC:
               cout << "the ESCAPE key." << endl;
               break;
               default:
               cout << "the [" << keyPress << "] key." << endl;
               break;
             }
        }
      } while (1);
      
    return 0;
}

Though I'm sure there are functions in some header that already did this for you. Perhaps windows.h or something.

Oh well, look around or do something like this.

...and for the hell of it, here is a program that uses the arrowkeys:

Code:

/* *************************************************
  Name: Active Movement Interfaces in DOS 
  Author: W---------------
  Date: 06/10/05 18:14
  Description: Demonstrates the use of the gotoxy()
  function and getch() fuction to create an active
  interface in a standard DOS program.
***************************************************/

#include <iostream.h>
#include <conio.h>     // Should contain a standard gotoxy() function, but
                       // mine doesn't for some reason, so I defined it 
                       // accessing Windows API directly.
#include <windows.h>   // Needed for the gotoxy() function I used.
                    
void gotoxy(int x, int y);                    
                    
int main()
{
    const char UPKEY = 72;
    const char LEFTKEY = 75;
    const char RIGHTKEY = 77;
    const char DOWNKEY = 80;
   
    int horiAXIS = 2;
    int vertAXIS = 2;
    int keyPress;
    
    cout << "Press the arrow keys to move the \"o\"." << endl << endl;
    cout << "  o";
    
    while (1) 
    {
          
          keyPress = getch();
          
          switch(keyPress)
             {
               case UPKEY:
                    if (vertAXIS > 1)
                      vertAXIS = vertAXIS - 1; 
               break; 
               case DOWNKEY:
                    vertAXIS = vertAXIS + 1;  
               break;
               case LEFTKEY:
                    if (horiAXIS > 0)
                      horiAXIS = horiAXIS - 1;
               break;
               case RIGHTKEY:
                    horiAXIS = horiAXIS + 1;
               break;
             }
             
          cout << " ";                 //Clears the last character.
          gotoxy(horiAXIS,vertAXIS);
          cout << "o";                 //Creates the new character.
          gotoxy(horiAXIS,vertAXIS);   //Returns to standard space after print.
    
    } 
    
    return 0;   
}
                   
// I didn't write the following gotoxy() function. It can be found at:
// http://spike.scu.edu.au/~jmaltby/c.html                    
void gotoxy(int x, int y)
{
HANDLE hConsoleOutput;
COORD dwCursorPosition;

dwCursorPosition.X = x;
dwCursorPosition.Y = y;
hConsoleOutput = GetStdHandle(STD_OUTPUT_HANDLE);
SetConsoleCursorPosition(hConsoleOutput,dwCursorPosition);
}