op precedence in C

[utzoo!decvax!harpo!npoiv!alice!rabbit!ark]

It may be that

	c = getchar();
	if (c & 0177 == '\004')

should mask the parity bit off the character and then compare
it with a ctrl-d, but in fact it doesn't because & is lower
precedence than == .  You need to write

	if ((c & 0177) == '\004')

On the other hand, you can test if y is between x and z by saying

	if (x <= y & y <= z)

and it will work!  Of course

	if (x <= y && y <= z)

is better (by almost any reasonable measure).