Killing the comma operator

Steven Schveighoffer via Digitalmars-d digitalmars-d at puremagic.com
Wed May 11 07:08:28 PDT 2016


On Wednesday, 11 May 2016 at 13:29:56 UTC, Gopan wrote:
> On Tuesday, 10 May 2016 at 09:52:07 UTC, Mathias Lang wrote:
>
>>
>> Do you like comma expressions, ...
>
> I am a student.
> In C, one scenario where I like comma is this.
>
>
> int x;
> while( scanf("%d", &x),  x!= 0) // until user input 0.
> {
>    //do something with x
> }
>
> Without the comma operator, I would have to repeat the scanf 
> statement.
> int x;
> scanf("%d", &x);
> while(x != 0)
> {
>    //do something with x
>    scanf("%d", &x);
> }
>
> Does anybody think that this is a useful case of comma operator?

What if scanf fails or hits eof?

A better call:

while(scanf("%d", &x) > 0 && x != 0)

-Steve


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