Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>An obvious example would be the typical overload of ">>" as a stream extraction operator. To work as designed, this has to be able to modify both its left- and right-hand arguments. The right has to be modified, because the primary purpose is to read a new value into that variable. The left has to be modified to do things like indicating the current status of the stream.</p> <p>In theory, you could pass a pointer as the right-hand argument, but to do the same for the left argument would be problematic (e.g. when you chain operators together).</p> <p>Edit: it becomes more problematic for the left side partly because the basic syntax of overloading is that x@y (where "@" stands for any overloaded operator) means <code>x.opertor@(y)</code>. Now, if you change the rules so you somehow turn that <code>x</code> into a pointer, you quickly run into another problem: for a pointer, a lot of those operators already have a valid meaning separate from the overload -- e.g., if I translate <code>x+2</code> as somehow magically working with a pointer to <code>x</code>, then I've produced an expression that already has a meaning completely separate from the overload. To work around that, you could (for example) decide that for this purpose, you'd produce a special kind of pointer that didn't support pointer arithmetic. Then you'd have to deal with <code>x=y</code> -- so the special pointer becomes one that you can't modify directly either, and any attempt at assigning to it ends up assigning to whatever it points at instead.</p> <p>We've only restricted them enough to support two operator overloads, but our "special pointer" is already about 90% of the way to being a reference with a different name...</p>
    singulars
    1. This table or related slice is empty.
    1. POreferences in C++
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USJerry Coffin
    1. USJerry Coffin
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COplease elaborate on the last sentence you wrote... why would it be problematic for the left side?
      singulars
      1. PO
      1. USaherlambang
    2. COBecause then you'd have to call it something like: `(&cin)>>&n`, which is obviously ugly.
      singulars
      1. PO
      1. USBlindy
    3. CO@Blindy: not only that, but when you chain operators like: `cin>>x>>y`, the temporary would have to be a pointer -- and (as pointed out in my edit) you'd quickly have to make special rules for the pointers to keep things like `x+y+z` from being (completely allowable) operations on the pointers themselves instead of the object they pointed at.
      singulars
      1. PO
      1. USJerry Coffin
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload