There is no real ascii codes for these keys as such, you will need to check out the scan codes for these keys, known as Make and Break key codes as per helppc's information. The reason the codes sounds 'ascii' is because the key codes are handled by the old BIOS interrupt 0x16 and keyboard interrupt 0x9.
Normal Mode Num lock on
Make Break Make Break
Down arrow E0 50 E0 D0 E0 2A E0 50 E0 D0 E0 AA
Left arrow E0 4B E0 CB E0 2A E0 4B E0 CB E0 AA
Right arrow E0 4D E0 CD E0 2A E0 4D E0 CD E0 AA
Up arrow E0 48 E0 C8 E0 2A E0 48 E0 C8 E0 AA
Hence by looking at the codes following E0 for the Make key code, such as 0x50, 0x4B, 0x4D, 0x48 respectively, that is where the confusion arise from looking at key-codes and treating them as 'ascii'... the answer is don't as the platform varies, the OS varies, under Windows it would have virtual key code corresponding to those keys, not necessarily the same as the BIOS codes, VK_UP, VK_DOWN, VK_LEFT, VK_RIGHT.. this will be found in your C++'s header file windows.h, as I recall in the SDK's include folder.
Do not rely on the key-codes to have the same 'identical ascii' codes shown here as the Operating system will reprogram the entire BIOS code in whatever the OS sees fit, naturally that would be expected because since the BIOS code is 16bit, and the OS (nowadays are 32bit protected mode), of course those codes from the BIOS will no longer be valid.
Hence the original keyboard interrupt 0x9 and BIOS interrupt 0x16 would be wiped from the memory after the BIOS loads it and when the protected mode OS starts loading, it would overwrite that area of memory and replace it with their own 32 bit protected mode handlers to deal with those keyboard scan codes.
Here is a code sample from the old days of DOS programming, using Borland C v3:
#include <bios.h>
int getKey(void){
int key, lo, hi;
key = bioskey(0);
lo = key & 0x00FF;
hi = (key & 0xFF00) >> 8;
return (lo == 0) ? hi + 256 : lo;
}
This routine actually, returned the codes for up, down is 328 and 336 respectively, (I do not have the code for left and right actually, this is in my old cook book!) The actual scancode is found in the lo variable. Keys other than the A-Z,0-9, had a scan code of 0 via the bioskey routine.... the reason 256 is added, because variable lo has code of 0 and the hi variable would have the scan code and adds 256 on to it in order not to confuse with the 'ascii' codes...
Gaa! Go to asciitable.com. The arrow keys are the control equivalent of the HJKL keys. I.e., in vi create a big block of text. Note you can move around in that text using the HJKL keys. The arrow keys are going to be ^H, ^J, ^K, ^L.
At asciitable.com find, "K" in the third column. Now, look at the same row in the first column to find the matching control-code ("VT" in this case).
this is what i get:
Left - 19 Up - 5 Right - 4 Down - 24
Works in Visual Fox Pro
The ascii values of the:
Up key - 224 72
Down key - 224 80
Left key - 224 75
Right key - 224 77
Each of these has two integer values for ascii value, because they are special keys, as opposed to the code for $, which is simply 36. These 2 byte special keys usually have the first digit as either 224, or 0. this can be found with the F# in windows, or the delete key.
EDIT : This may actually be unicode looking back, but they do work.
In short:
left arrow: 37
up arrow: 38
right arrow: 39
down arrow: 40
You can check it by compiling,and running this small C++ program.
#include <iostream>
#include <conio.h>
#include <cstdlib>
int show;
int main()
{
while(true)
{
int show = getch();
std::cout << show;
}
getch(); // Just to keep the console open after program execution
}
You can utilzed the special function for activating the navigation for your programming purpose. Below is the sample code for it.
void Specialkey(int key, int x, int y)
{
switch(key)
{
case GLUT_KEY_UP:
/*Do whatever you want*/
break;
case GLUT_KEY_DOWN:
/*Do whatever you want*/
break;
case GLUT_KEY_LEFT:
/*Do whatever you want*/
break;
case GLUT_KEY_RIGHT:
/*Do whatever you want*/
break;
}
glutPostRedisplay();
}
Add this to your main function
glutSpecialFunc(Specialkey);
Hope this will to solve the problem!
Really the answer to this question depends on what operating system and programming language you are using. There is no "ASCII code" per se. The operating system detects you hit an arrow key and triggers an event that programs can capture. For example, on modern Windows machines, you would get a WM_KEYUP or WM_KEYDOWN event. It passes a 16-bit value usually to determine which key was pushed.
If you're programming in OpenGL, use GLUT. The following page should help: http://www.lighthouse3d.com/opengl/glut/index.php?5
GLUT_KEY_LEFT Left function key
GLUT_KEY_RIGHT Right function key
GLUT_KEY_UP Up function key
GLUT_KEY_DOWN Down function key
void processSpecialKeys(int key, int x, int y) {
switch(key) {
case GLUT_KEY_F1 :
red = 1.0;
green = 0.0;
blue = 0.0; break;
case GLUT_KEY_F2 :
red = 0.0;
green = 1.0;
blue = 0.0; break;
case GLUT_KEY_F3 :
red = 0.0;
green = 0.0;
blue = 1.0; break;
}
}
The Ascii codes for arrow characters are the following: ? 24 ? 25 ? 26 ? 27
Source: Stackoverflow.com