Re: on allowing "int a" definition everywhere

On 21/08/2024 09:34, Bart wrote:

On 21/08/2024 12:17, Thiago Adams wrote:

On 21/08/2024 01:42, Blue-Maned_Hawk wrote:

Thiago Adams wrote:
>

initializer inside if is already in C++, and it will probably be on C2Y.

If it's for consistency with how for loops permit declarations, i would
_much_  prefer that they just outlaw that to induce consistency.
>
(Really, i'd ideally want things to just stay as they are, since
declarations in for loops are simply too useful for macros.)

>
I like the ability to declare things inside if.
>
if (FILE* f = fopen("file.txt", "r"))
{
   /*...*/
   fclose(f);
}
>
Because it makes the scope of f, associated with the pointed object lifetime.
>
For instance, if you try to use f
>
if (FILE* f = fopen("file.txt", "r"))
{
   /*...*/
   fclose(f);
}
fwrite(f, ..) ;// ERROR

 Run-time or compile-time error?

Compile time. f is not visible outside.

 It won't be a compile-time error if there is another 'f' visible in that outer scope.
 And it won't be one here either:
   if (FILE* f = fopen("file.txt", "r"))
  {
     /*...*/
     fclose(f);
     fwrite(f, ..) ;// ERROR
  }
 

For this type of error you need my static analyzer. (cake) :D
http://thradams.com/cake/playground.html?code=I3ByYWdtYSBzYWZldHkgZW5hYmxlCiNpbmNsdWRlIDxzdGRpby5oPgppbnQgbWFpbigpCnsKICAgRklMRSogX093bmVyIF9PcHQgZjsKICAgaWYgKCBmID0gZm9wZW4oImZpbGUudHh0IiwgInIiKSkKICAgewogICAgY2hhciBhW109ImFiIjsKICAgIGZjbG9zZShmKTsgICAgIAogICAgZndyaXRlKGEsIDEsIDIsIGYpOyAgICAgCiAgIH0KfQo%3D&to=-1&options=

Meanwhile, I'd have a serious problem with the extra clutter this causes. Since you are not reporting an fopen failure, I'd write this as:
    FILE* f;
    f = fopen("file.txt", "r");
   if (f) {
      // ...
      fclose(f);
   }
 However I'd be more likely check for failure first.

It is something optional to use.

Since I did a recent survery where, on a average, functions only had 3 local variables (in a selection of apps), I've been even more sceptical of block-scoped variables.