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From: Richard Heathfield <rjh@cpax.org.uk>
Newsgroups: comp.lang.c
Subject: Re: Suggested method for returning a string from a C program?
Date: Wed, 19 Mar 2025 21:21:27 +0000
Organization: Fix this later
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On 19/03/2025 20:45, DFS wrote:
> On 3/19/2025 4:53 AM, Keith Thompson wrote:

<snip>

>> I'm actually using
>> scanf() for integer input, something I wouldn't do in normal code
>> (because the behavior is undefined if the scanned value is out
>> of range).  This is a rare case where it's safe to assume that
>> stdin has nothing harmful.
> 
> 
> 
> My very 1st submission for 'Missing Number' was accepted, but 
> each use of scanf() generated a warning:

Like Keith, I don't usually use scanf.

My preference is to read the number into a text buffer using 
fgets, and then convert it using strtoul if I can, or strtol if I 
have to allow for negatives.

> //identify the missing number in a set of consecutive integers

Not sure why you're sorting and malloc-ing.

Loop through the input, adding as you go.
Let the first number be x.
Let the last number be y.
Let the total of all numbers be t.
Let m = ((y*(y+1))-(x*(x+1)))/2 - t;

"The missing number is: %lld\n", m

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
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