Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <blockquote> <p>However, on compilation, only the method defined in C is recognized, and potential() isn't seen (this should have been inherited from B).</p> </blockquote> <p>C++ doesn’t work like this: because you implemented a different <code>potential</code> method (a method of the same name but with different parameters) in <code>C</code>, the other method is <em>hidden</em> as far as <code>C</code> is concerned.</p> <p>Hiding happens because of the way that C++ resolves (overloaded) method names: when you call a method <code>potential</code> on an instance of a class (here <code>c</code>), C++ searches in the class whether a method of that name exists. If that isn’t the case it continues its search in the base classes. It goes further up in the hierarchy until at least one method of that name is found.</p> <p>But in your case, C++ doesn’t have to search far: the method already exists in <code>C</code>, so it stops its search. Now C++ tries to match the method signature. Unfortunately, the method signature doesn’t match but at this time it’s too late: overload resolution fails; C++ doesn’t search for other methods that might match.</p> <p>There are three solutions:</p> <ol> <li><p>Import it with <code>using</code> in C:</p> <pre><code>class C : public B { public: using B::potential; int potential(int arg, int arg2) { return 3; } }; </code></pre></li> <li><p>Call the method from a base class instance in <code>main</code>:</p> <pre><code>C c; B&amp; b = c; int value = b.potential(); </code></pre></li> <li><p>Qualify the name explicitly in <code>main</code>:</p> <pre><code>C c; int value = c.B::potential(); </code></pre></li> </ol>
    singulars
    1. This table or related slice is empty.
    1. POUnderstanding (simple?) C++ Inheritance
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USKonrad Rudolph
    1. USKonrad Rudolph
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POUnderstanding (simple?) C++ Inheritance
      singulars
      1. PTQuestion
    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. COInteresting - I haven't seen the `using` keyword used like this, before. How come the other method is hidden? It has a different signature than the defined method, right?
      singulars
      1. PO
      1. USDan
    2. CO@Dan: That's just the way inheritance is in C++. Call it a quirk if you like.
      singulars
      1. PO
      1. USLightness Races in Orbit
    3. CO@Dan I’ve added an explanation of overload resolution and hiding.
      singulars
      1. PO
      1. USKonrad Rudolph
 

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