ncurses nodelay for responsive arrow key feedback - ncurses

Question

I am trying to write integers to a file using ncurses and the keyboard arrows. I use nodelay so that I can write a 4 to the file while nothing is being pressed. ESC exits the program. The problem is that all I can ever write to the files is 4. ESC seems to work fine, so the switch is working. If I take out the nodelay the program works but 4 cannot ever be writen.
Thanks
#include <ncurses.h>
#include <fstream>
using namespace std;
int main(int argc, char* argv[])
{
ofstream outFile;
char outputFilename[80];
sprintf(outputFilename, "files/file.%s",argv[1]);
outFile.open(outputFilename, ios::out);
int ch;
initscr();
nodelay(stdscr,TRUE);
raw();
keypad(stdscr, TRUE);
noecho();
refresh();
while(1){
ch = getch();
switch(ch)
{
case KEY_UP:
outFile << 0 << endl;
break;
case KEY_DOWN:
outFile << 1 << endl;
break;
case KEY_RIGHT:
outFile << 2 << endl;
break;
case KEY_LEFT:
outFile << 3 << endl;
break;
case ERR:
outFile << 4 << endl;
break;
case 27:
outFile.close();
endwin();
return 0;
break;
default:
break;
}
refresh();
}
}

Answer 1

I was able to fix this issue by checking to see if the last value of ch was ERR before writing 4 to the file. Not sure I understand completely... maybe a timing issue. New program:
#include <ncurses.h>
#include <fstream>
using namespace std;
int main(int argc, char* argv[])
{
ofstream outFile;
char outputFilename[80];
sprintf(outputFilename, "interactive/taker.%s",argv[1]);
outFile.open(outputFilename, ios::out);
int ch;
int ch_prev=0;
initscr();
nodelay(stdscr,TRUE);
raw();
keypad(stdscr, TRUE);
noecho();
while(1){
ch = getch();
switch(ch)
{
case KEY_UP:
outFile << 0 << endl;
break;
case KEY_DOWN:
outFile << 1 << endl;
break;
case KEY_RIGHT:
outFile << 2 << endl;
break;
case KEY_LEFT:
outFile << 3 << endl;
break;
case ERR:
if (ch_prev != ERR)
outFile << 4 << endl;
break;
case 27:
outFile.close();
endwin();
return 0;
break;
default:
break;
}
ch_prev=ch;
refresh();
}
}

Answer 2

Without the check, you will overlook the lines which are not 4's, since almost all of the return values are ERR's. Also - the program will be using a lot of CPU (doing nothing). You would get better results if you used timeout with a fairly short value (10-50 milliseconds) rather than nodelay.