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Should I explicitly delete structs in C++? [duplicate]

0

This question already has an answer here:

• 
  When to use “delete”?
  
  5 answers
  
  


• 
  C++ and when to use delete
  
  4 answers
  
  


• 
  Calling delete on variable allocated on the stack
  
  11 answers
  
  


• 
  Do I have to delete struct pointer manually in C++?
  
  4 answers
  
  

Let's say I have a struct defined as so:

struct Barre 
 int startString;
 int endString;

 Barre() startString = endString = -1; 
 Barre(int s, int e) : startString(s), endString(e) 
 bool exists() return startString > -1; 
 ;

I will create an instance of this struct like this, for example:

Barre b = Barre(2, 4);

Let's say I insert this into a std::map<int, Barre> which is a member of a class, with a key of, for example, 3.

If I then create another Barre as above and overwrite the value of the map at key 3 with this new instance of the Barre struct, do I need to explicitly delete the old Barre object that I'm overwriting to prevent memory leaks? Or does it not persist once it is no longer stored in a map in this way?

Thanks for any help.

c++ oop struct memory-leaks

share|improve this question

asked Mar 7 at 17:16

JThistleJThistle

11711

marked as duplicate by πάντα ῥεῖ c++
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Mar 7 at 17:19

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Also, as a rule of thumb for modern C++ (C++11 and later), you really shouldn't ever need to use new and especially not delete yourself, unless you are doing some pretty deep library development, or use some existing framework which requires you to use them for legacy reasons (for example with Qt you'll use new, but don't need delete, and C++11 doesn't yet have make_unique function). Instead, use smart pointers.
  
  – hyde
  Mar 7 at 17:25
  
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  @JThistle "it's worth noting that I have searched for an answer to this and can't find anything." Well, this was the google query I used to find the duplicate questions: c++ when do i need delete site:stackoverflow.com
  
  – πάντα ῥεῖ
  Mar 7 at 17:27
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I used 'do I need to delete a struct' and variations on that, DuckDuckGo returned nothing helpful.
  
  – JThistle
  Mar 7 at 17:30
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  @JThistle The problem with your query might possibly have been that you searched for struct specifically, which is completely irrelevant for the question. A struct is just the same as a class with all members public as default. Nothing to do with dynamic memory management at all.
  
  – πάντα ῥεῖ
  Mar 7 at 17:36
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @πάνταῥεῖ When reading questions, it's good to keep in mind that things that are self-evident for someone who knows a language, necessarily aren't that for everybody, even experienced programmers. For example a C# developer (I don't know if OP is) entering C++ world might have a bit of WTF moment when they learn that struct and class are basically the same thing, and until that realization might have trouble formulating a suitable search engine query.
  
  – hyde
  Mar 7 at 18:23
  

  
  
  
  

 | 
show 4 more comments

0

This question already has an answer here:

• 
  When to use “delete”?
  
  5 answers
  
  


• 
  C++ and when to use delete
  
  4 answers
  
  


• 
  Calling delete on variable allocated on the stack
  
  11 answers
  
  


• 
  Do I have to delete struct pointer manually in C++?
  
  4 answers
  
  

Let's say I have a struct defined as so:

struct Barre 
 int startString;
 int endString;

 Barre() startString = endString = -1; 
 Barre(int s, int e) : startString(s), endString(e) 
 bool exists() return startString > -1; 
 ;

I will create an instance of this struct like this, for example:

Barre b = Barre(2, 4);

Let's say I insert this into a std::map<int, Barre> which is a member of a class, with a key of, for example, 3.

If I then create another Barre as above and overwrite the value of the map at key 3 with this new instance of the Barre struct, do I need to explicitly delete the old Barre object that I'm overwriting to prevent memory leaks? Or does it not persist once it is no longer stored in a map in this way?

Thanks for any help.

c++ oop struct memory-leaks

share|improve this question

asked Mar 7 at 17:16

JThistleJThistle

11711

marked as duplicate by πάντα ῥεῖ c++
Users with the  c++ badge can single-handedly close c++ questions as duplicates and reopen them as needed.

StackExchange.ready(function()
if (StackExchange.options.isMobile) return;

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var $hover = $(this).addClass('hover-bound'),
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StackExchange.helpers.removeMessages();

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Mar 7 at 17:19

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Also, as a rule of thumb for modern C++ (C++11 and later), you really shouldn't ever need to use new and especially not delete yourself, unless you are doing some pretty deep library development, or use some existing framework which requires you to use them for legacy reasons (for example with Qt you'll use new, but don't need delete, and C++11 doesn't yet have make_unique function). Instead, use smart pointers.
  
  – hyde
  Mar 7 at 17:25
  
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  @JThistle "it's worth noting that I have searched for an answer to this and can't find anything." Well, this was the google query I used to find the duplicate questions: c++ when do i need delete site:stackoverflow.com
  
  – πάντα ῥεῖ
  Mar 7 at 17:27
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I used 'do I need to delete a struct' and variations on that, DuckDuckGo returned nothing helpful.
  
  – JThistle
  Mar 7 at 17:30
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  @JThistle The problem with your query might possibly have been that you searched for struct specifically, which is completely irrelevant for the question. A struct is just the same as a class with all members public as default. Nothing to do with dynamic memory management at all.
  
  – πάντα ῥεῖ
  Mar 7 at 17:36
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @πάνταῥεῖ When reading questions, it's good to keep in mind that things that are self-evident for someone who knows a language, necessarily aren't that for everybody, even experienced programmers. For example a C# developer (I don't know if OP is) entering C++ world might have a bit of WTF moment when they learn that struct and class are basically the same thing, and until that realization might have trouble formulating a suitable search engine query.
  
  – hyde
  Mar 7 at 18:23
  

  
  
  
  

 | 
show 4 more comments

This question already has an answer here:

• 
  When to use “delete”?
  
  5 answers
  
  


• 
  C++ and when to use delete
  
  4 answers
  
  


• 
  Calling delete on variable allocated on the stack
  
  11 answers
  
  


• 
  Do I have to delete struct pointer manually in C++?
  
  4 answers
  
  

Let's say I have a struct defined as so:

struct Barre 
 int startString;
 int endString;

 Barre() startString = endString = -1; 
 Barre(int s, int e) : startString(s), endString(e) 
 bool exists() return startString > -1; 
 ;

I will create an instance of this struct like this, for example:

Barre b = Barre(2, 4);

Let's say I insert this into a std::map<int, Barre> which is a member of a class, with a key of, for example, 3.

If I then create another Barre as above and overwrite the value of the map at key 3 with this new instance of the Barre struct, do I need to explicitly delete the old Barre object that I'm overwriting to prevent memory leaks? Or does it not persist once it is no longer stored in a map in this way?

Thanks for any help.

c++ oop struct memory-leaks

share|improve this question

asked Mar 7 at 17:16

JThistleJThistle

11711

struct Barre 
 int startString;
 int endString;

 Barre() startString = endString = -1; 
 Barre(int s, int e) : startString(s), endString(e) 
 bool exists() return startString > -1; 
 ;

Barre b = Barre(2, 4);

share|improve this question

asked Mar 7 at 17:16

JThistleJThistle

11711

share|improve this question

asked Mar 7 at 17:16

JThistleJThistle

11711

asked Mar 7 at 17:16

JThistleJThistle

11711

asked Mar 7 at 17:16

JThistleJThistle

11711