The programmer may then use the names TRUE and FALSE in his/her source file, confident that these will be replaced with the constants 1 and 0 upon compilation:
done = FALSE;
while (!done)
{
if ((c = getchar()) == 'x')
done = TRUE;
else
.
.
}
It is good programming practice to use this technique whenever a numerical constant is used, to help identify the purpose of this constant and to simplify future changes: