why do I get the same value of "up down right left" key-press from getch()

Question

I write a small program about B-Trix. And I want to use getch() to get gamer's input. I try to get the value of up,down,right,left key-press by using getch(), here is my test code:

#include <stdio.h>
#include <curses.h>
int main(void)
{
int ch;
initscr();
printw("Input a character:");
ch = getch();
printw("\nYou input a '%c'\n%d", ch, ch);
refresh();
sleep(3);
endwin();
return 0;
}

the outputs of up down left right are 27, why are these value same? Could anybody help me?

Answer 1

The arrow keys were encoded by three characters in Ubuntu. So I changed my code like this to check arrow keys.

if(kbhit()){
            switch(getch()){
            case 0x1b:          //For case arrow pressed
                if(getch() == 0x5b){
                    switch(getch()){
                    case 0x41:
                        turn();
                        break;
                    case 0x44:
                        mv_left();
                        break;
                    case 0x43:
                        mv_right();
                        break;
                    case 0x42:
                        mv_down();
                        break;
                    }
                }
                break;
            }
}