Pascal vs C, again (was: Pascals Origins)

[Marty Smith]

In article <3130 at utcsri.UUCP> greg at utcsri.UUCP (Gregory Smith) writes:
>
>Challenge: given
>
>var	x: array [1..1000] of integer;
>
>write a code fragment to find the location of the first 0 in x. The
>condition that no zeroes exist must be distinguished.
>
>Further rules:
>	- Standard Jensen & Wirth Pascal ( no break from loop )
>	- *** x[i] must not be evaluated for i<1 or i>1000 ***
>	- The search loop must be terminated as soon as a zero is found.
>	- 'a or b', 'a and b' always evaluate both a and b ( I think
>	   this is a rule in Jensen & Wirth )
>
>This is the best I can find:
>	var i: integer;
>	...
>	i :=1 ;
>	while i<1000 and x[i] <> 0 do
>		i := i+1;
>	if x[i] = 0 then writeln('zero at location', i )
>	else writeln('not found');
>
>weird,huh? Note that the condition 'x[i]=0' is evaluated twice ( once
>in the negative sense ), which would be unacceptable if we were searching
>an array of records and the test was expensive.
>
What's wrong with this one?

	label 1,2;
	var i: integer;
	...
	i :=1 ;
	while i<=1000 do
		if x[i] = 0 then goto 1
		else i := i+1;

	writeln('not found');
	goto 2;
1:      writeln('zero at location', i )
2:      ...



		  Martin Smith