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From: hunt@spar.SPAR.SLB.COM (Neil Hunt)
Newsgroups: comp.lang.c
Subject: Re: Printing binary (was: Re: Why college?)
Message-ID: <1646@spar.SPAR.SLB.COM>
Date: Fri, 23-Oct-87 13:44:24 EST
Article-I.D.: spar.1646
Posted: Fri Oct 23 13:44:24 1987
Date-Received: Sun, 25-Oct-87 18:38:38 EST
References: <35@ateng.UUCP> <3194@sol.ARPA> <2783@xanth.UUCP> <235@snark.UUCP> <2072@watcgl.waterloo.edu>
Reply-To: hunt@spar.UUCP (Neil Hunt)
Organization: Schlumberger Palo Alto Research - CASLAB
Lines: 40

This is crying out for recursion:

	/*
	 * print_binary:
	 *	Prints `value' in binary with `bits' digits.
	 */

	void
	print_binary(value, bits)
	int value, bits;
	{
		if(--bits > 0)
			print_binary(value >> 1, bits);

		putchar((value & 0x1) + '0');
	}

To print without extra leading zeros or ones (that is if the value is
positive, print a single 0 then the actual number, if it is negative,
print a single 1 and then the actual number):

	/*
	 * print_normalised_binary:
	 *	Prints `value' in binary with sign bit in normalised position.
	 *	Assumes a sign extending '>>'.
	 */

	void
	print_normalised_binary(value)
	int value;
	{
		if(value != 0 && value != -1)
			print_normalised_binary(value >> 1);

		putchar((value & 0x1) + '0');
	}

Exercise 1a: rewrite the above functions for printing hexadecimal and octal

Neil/.