How to make a dynamic storage of objects (c++)

up vote
0
down vote

favorite

I am a beginner to programming and I am trying to find a way to create a dynamic storage of objects of my pigeon class. Here is my code:

class pigeon {

public:

    pigeon(std::string nameI);

    void outputInfo();

private:

    std::string name;

};

The idea is that I want to be able to add a new object, have a place to store its information, then be able to add another object, and so on. I have no idea where to start with this or even what data structure to use, I have no experience storing objects.

asked Nov 21 at 22:13

NipIsTrue

195

4

Are the objects you want to store of the same type? If so you can simply use a std::vector<YourObject>
– Zpalmtree
Nov 21 at 22:14

4

std::vector
– François Andrieux
Nov 21 at 22:15

You need to indicate in your question what you mean by store. Do you mean in memory or something more permanent?
– Kit
Nov 21 at 22:17

As @FrançoisAndrieux already said. Use a std::vector.
– Jesper Juhl
Nov 21 at 22:37

add a comment |

up vote
0
down vote

favorite

I am a beginner to programming and I am trying to find a way to create a dynamic storage of objects of my pigeon class. Here is my code:

class pigeon {

public:

    pigeon(std::string nameI);

    void outputInfo();

private:

    std::string name;

};

asked Nov 21 at 22:13

NipIsTrue

195

4

Are the objects you want to store of the same type? If so you can simply use a std::vector<YourObject>
– Zpalmtree
Nov 21 at 22:14

4

std::vector
– François Andrieux
Nov 21 at 22:15

You need to indicate in your question what you mean by store. Do you mean in memory or something more permanent?
– Kit
Nov 21 at 22:17

As @FrançoisAndrieux already said. Use a std::vector.
– Jesper Juhl
Nov 21 at 22:37

add a comment |

up vote
0
down vote

favorite

I am a beginner to programming and I am trying to find a way to create a dynamic storage of objects of my pigeon class. Here is my code:

class pigeon {

public:

    pigeon(std::string nameI);

    void outputInfo();

private:

    std::string name;

};

asked Nov 21 at 22:13

NipIsTrue

195

I am a beginner to programming and I am trying to find a way to create a dynamic storage of objects of my pigeon class. Here is my code:

class pigeon {

public:

    pigeon(std::string nameI);

    void outputInfo();

private:

    std::string name;

};

c++ data-structures

asked Nov 21 at 22:13

NipIsTrue

195

asked Nov 21 at 22:13

NipIsTrue

195

asked Nov 21 at 22:13

NipIsTrue

195

asked Nov 21 at 22:13

NipIsTrue

195

asked Nov 21 at 22:13

NipIsTrue

195

4

Are the objects you want to store of the same type? If so you can simply use a std::vector<YourObject>
– Zpalmtree
Nov 21 at 22:14

4

std::vector
– François Andrieux
Nov 21 at 22:15

You need to indicate in your question what you mean by store. Do you mean in memory or something more permanent?
– Kit
Nov 21 at 22:17

As @FrançoisAndrieux already said. Use a std::vector.
– Jesper Juhl
Nov 21 at 22:37

add a comment |

4

Are the objects you want to store of the same type? If so you can simply use a std::vector<YourObject>
– Zpalmtree
Nov 21 at 22:14

4

std::vector
– François Andrieux
Nov 21 at 22:15

You need to indicate in your question what you mean by store. Do you mean in memory or something more permanent?
– Kit
Nov 21 at 22:17

As @FrançoisAndrieux already said. Use a std::vector.
– Jesper Juhl
Nov 21 at 22:37

Are the objects you want to store of the same type? If so you can simply use a std::vector<YourObject>
– Zpalmtree
Nov 21 at 22:14

std::vector
– François Andrieux
Nov 21 at 22:15

You need to indicate in your question what you mean by store. Do you mean in memory or something more permanent?
– Kit
Nov 21 at 22:17

As @FrançoisAndrieux already said. Use a std::vector.
– Jesper Juhl
Nov 21 at 22:37

add a comment |

3 Answers
3

active

oldest

votes

up vote
0
down vote

Make vector with pointer of your class:

std::vector<pigeon*> pigeons;

Then allocate new pigeon object and push it into your vector:

pigeon * pig = new pigeon("pigeon");

pigeons.push_back(pig);

answered Nov 21 at 22:52

kara

576

1

Is there a reason you suggest using raw owning pointers and adding another level of indirection where std::vector<pigeon> already does what the OP wants?
– Swordfish
Nov 21 at 23:28

Op wants to store dynamic objects. When you use vector<pigeon> it first copies the object and stores it. This is not dynamic storing. And some point of view it is not efficient.
– kara
Nov 21 at 23:39

1

There is always emplace_back() and smart pointers.
– Swordfish
Nov 21 at 23:42

Can you give an example of usage of these?
– kara
Nov 21 at 23:46

2

If copying objects is very expensive, don't copy. There are better ways like having a collection of indexes around that you reorder instead of the objects in the vector. Maybe use a std::list<std::unique_ptr<pigeon>>.
– Swordfish
Nov 22 at 0:30

|
show 4 more comments

up vote
0
down vote

As it was already pointed out in the comments, you should preferably use a container that handles its resources following the RAII/RDID-idiom ( "Resource Acquisition Is Initialisation" / "Resource Destruction is Deletion") so you don't have to worry about it yourself. This is also a simple way of preventing resource leaks when an exception is thrown.

One of the commonly used containers of the C++ standard library is std::vector<>.

You'd use it like this (just to give you an initial idea, please refer to the documentation for further explanation and examples):

#include <vector>



// ...



{

    std::vector<pigeon> pigeons;



    pigeons.push_back("Karl");   // add three pigeons

    pigeons.push_back("Franz");  // at the end of the

    pigeons.push_back("Xaver");  // vector



    pigeons[1]; // access "Franz"



    for(auto /* maybe const */ &p : pigeons) {  // iterate over the vector

        // do something with pigeon p

    }



} // pigeons goes out of scope, its destructor is called which

  // takes care of deallocating the memory used by the vector.

edited Nov 21 at 23:51

answered Nov 21 at 23:39

Swordfish

add a comment |

up vote
-2
down vote

You can allocate storage using new like that:
pigeon *pigeon_array = new pigeon[SIZE]

In SIZE you must enter how many elements do you want to store.But dont forget use delete pigeon_array when u will dont need this array anymore.

Or you can use std::vector or std::array

answered Nov 21 at 22:35

Fqqlt

2

Please don't advocate manual memory management in 2018... "Or you can use std::vector or std::array" - Not or, do!
– Jesper Juhl
Nov 21 at 22:38

I am don't advocate manual memory management I want to show various ways to make a dynamic storage
– Fqqlt
Nov 21 at 22:42

When I mean dynamic I mean like I can add elements too it, so I don't know how many elements I am going to be storing initially
– NipIsTrue
Nov 21 at 22:48

@NipIsTrue Then use a std::vector.
– Jesper Juhl
Nov 21 at 22:53

So,you need to use std::vector for that
– Fqqlt
Nov 21 at 22:53

|
show 1 more comment

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3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

up vote
0
down vote

Make vector with pointer of your class:

std::vector<pigeon*> pigeons;

Then allocate new pigeon object and push it into your vector:

pigeon * pig = new pigeon("pigeon");

pigeons.push_back(pig);

answered Nov 21 at 22:52

kara

576

1

Is there a reason you suggest using raw owning pointers and adding another level of indirection where std::vector<pigeon> already does what the OP wants?
– Swordfish
Nov 21 at 23:28

Op wants to store dynamic objects. When you use vector<pigeon> it first copies the object and stores it. This is not dynamic storing. And some point of view it is not efficient.
– kara
Nov 21 at 23:39

1

There is always emplace_back() and smart pointers.
– Swordfish
Nov 21 at 23:42

Can you give an example of usage of these?
– kara
Nov 21 at 23:46

2

If copying objects is very expensive, don't copy. There are better ways like having a collection of indexes around that you reorder instead of the objects in the vector. Maybe use a std::list<std::unique_ptr<pigeon>>.
– Swordfish
Nov 22 at 0:30

|
show 4 more comments

up vote
0
down vote

Make vector with pointer of your class:

std::vector<pigeon*> pigeons;

Then allocate new pigeon object and push it into your vector:

pigeon * pig = new pigeon("pigeon");

pigeons.push_back(pig);

answered Nov 21 at 22:52

kara

576

1

Is there a reason you suggest using raw owning pointers and adding another level of indirection where std::vector<pigeon> already does what the OP wants?
– Swordfish
Nov 21 at 23:28

Op wants to store dynamic objects. When you use vector<pigeon> it first copies the object and stores it. This is not dynamic storing. And some point of view it is not efficient.
– kara
Nov 21 at 23:39

1

There is always emplace_back() and smart pointers.
– Swordfish
Nov 21 at 23:42

Can you give an example of usage of these?
– kara
Nov 21 at 23:46

2

If copying objects is very expensive, don't copy. There are better ways like having a collection of indexes around that you reorder instead of the objects in the vector. Maybe use a std::list<std::unique_ptr<pigeon>>.
– Swordfish
Nov 22 at 0:30

|
show 4 more comments

up vote
0
down vote

Make vector with pointer of your class:

std::vector<pigeon*> pigeons;

Then allocate new pigeon object and push it into your vector:

pigeon * pig = new pigeon("pigeon");

pigeons.push_back(pig);

answered Nov 21 at 22:52

kara

576

Make vector with pointer of your class:

std::vector<pigeon*> pigeons;

Then allocate new pigeon object and push it into your vector:

pigeon * pig = new pigeon("pigeon");

pigeons.push_back(pig);

answered Nov 21 at 22:52

kara

576

answered Nov 21 at 22:52

kara

576

answered Nov 21 at 22:52

kara

576

answered Nov 21 at 22:52

kara

576

1

Is there a reason you suggest using raw owning pointers and adding another level of indirection where std::vector<pigeon> already does what the OP wants?
– Swordfish
Nov 21 at 23:28

Op wants to store dynamic objects. When you use vector<pigeon> it first copies the object and stores it. This is not dynamic storing. And some point of view it is not efficient.
– kara
Nov 21 at 23:39

1

There is always emplace_back() and smart pointers.
– Swordfish
Nov 21 at 23:42

Can you give an example of usage of these?
– kara
Nov 21 at 23:46

2

If copying objects is very expensive, don't copy. There are better ways like having a collection of indexes around that you reorder instead of the objects in the vector. Maybe use a std::list<std::unique_ptr<pigeon>>.
– Swordfish
Nov 22 at 0:30

|
show 4 more comments

1

Is there a reason you suggest using raw owning pointers and adding another level of indirection where std::vector<pigeon> already does what the OP wants?
– Swordfish
Nov 21 at 23:28

Op wants to store dynamic objects. When you use vector<pigeon> it first copies the object and stores it. This is not dynamic storing. And some point of view it is not efficient.
– kara
Nov 21 at 23:39

1

There is always emplace_back() and smart pointers.
– Swordfish
Nov 21 at 23:42

Can you give an example of usage of these?
– kara
Nov 21 at 23:46

2

If copying objects is very expensive, don't copy. There are better ways like having a collection of indexes around that you reorder instead of the objects in the vector. Maybe use a std::list<std::unique_ptr<pigeon>>.
– Swordfish
Nov 22 at 0:30

Is there a reason you suggest using raw owning pointers and adding another level of indirection where std::vector<pigeon> already does what the OP wants?
– Swordfish
Nov 21 at 23:28

Op wants to store dynamic objects. When you use vector<pigeon> it first copies the object and stores it. This is not dynamic storing. And some point of view it is not efficient.
– kara
Nov 21 at 23:39

There is always emplace_back() and smart pointers.
– Swordfish
Nov 21 at 23:42

Can you give an example of usage of these?
– kara
Nov 21 at 23:46

If copying objects is very expensive, don't copy. There are better ways like having a collection of indexes around that you reorder instead of the objects in the vector. Maybe use a std::list<std::unique_ptr<pigeon>>.
– Swordfish
Nov 22 at 0:30

|
show 4 more comments

up vote
0
down vote

One of the commonly used containers of the C++ standard library is std::vector<>.

You'd use it like this (just to give you an initial idea, please refer to the documentation for further explanation and examples):

#include <vector>



// ...



{

    std::vector<pigeon> pigeons;



    pigeons.push_back("Karl");   // add three pigeons

    pigeons.push_back("Franz");  // at the end of the

    pigeons.push_back("Xaver");  // vector



    pigeons[1]; // access "Franz"



    for(auto /* maybe const */ &p : pigeons) {  // iterate over the vector

        // do something with pigeon p

    }



} // pigeons goes out of scope, its destructor is called which

  // takes care of deallocating the memory used by the vector.

edited Nov 21 at 23:51

answered Nov 21 at 23:39

Swordfish

add a comment |

up vote
0
down vote

One of the commonly used containers of the C++ standard library is std::vector<>.

You'd use it like this (just to give you an initial idea, please refer to the documentation for further explanation and examples):

#include <vector>



// ...



{

    std::vector<pigeon> pigeons;



    pigeons.push_back("Karl");   // add three pigeons

    pigeons.push_back("Franz");  // at the end of the

    pigeons.push_back("Xaver");  // vector



    pigeons[1]; // access "Franz"



    for(auto /* maybe const */ &p : pigeons) {  // iterate over the vector

        // do something with pigeon p

    }



} // pigeons goes out of scope, its destructor is called which

  // takes care of deallocating the memory used by the vector.

edited Nov 21 at 23:51

answered Nov 21 at 23:39

Swordfish

add a comment |

up vote
0
down vote

One of the commonly used containers of the C++ standard library is std::vector<>.

You'd use it like this (just to give you an initial idea, please refer to the documentation for further explanation and examples):

#include <vector>



// ...



{

    std::vector<pigeon> pigeons;



    pigeons.push_back("Karl");   // add three pigeons

    pigeons.push_back("Franz");  // at the end of the

    pigeons.push_back("Xaver");  // vector



    pigeons[1]; // access "Franz"



    for(auto /* maybe const */ &p : pigeons) {  // iterate over the vector

        // do something with pigeon p

    }



} // pigeons goes out of scope, its destructor is called which

  // takes care of deallocating the memory used by the vector.

edited Nov 21 at 23:51

answered Nov 21 at 23:39

Swordfish

One of the commonly used containers of the C++ standard library is std::vector<>.

You'd use it like this (just to give you an initial idea, please refer to the documentation for further explanation and examples):

#include <vector>



// ...



{

    std::vector<pigeon> pigeons;



    pigeons.push_back("Karl");   // add three pigeons

    pigeons.push_back("Franz");  // at the end of the

    pigeons.push_back("Xaver");  // vector



    pigeons[1]; // access "Franz"



    for(auto /* maybe const */ &p : pigeons) {  // iterate over the vector

        // do something with pigeon p

    }



} // pigeons goes out of scope, its destructor is called which

  // takes care of deallocating the memory used by the vector.

edited Nov 21 at 23:51

answered Nov 21 at 23:39

Swordfish

edited Nov 21 at 23:51

answered Nov 21 at 23:39

Swordfish

answered Nov 21 at 23:39

Swordfish

answered Nov 21 at 23:39

Swordfish

add a comment |

up vote
-2
down vote

You can allocate storage using new like that:
pigeon *pigeon_array = new pigeon[SIZE]

In SIZE you must enter how many elements do you want to store.But dont forget use delete pigeon_array when u will dont need this array anymore.

Or you can use std::vector or std::array

answered Nov 21 at 22:35

Fqqlt

2

Please don't advocate manual memory management in 2018... "Or you can use std::vector or std::array" - Not or, do!
– Jesper Juhl
Nov 21 at 22:38

I am don't advocate manual memory management I want to show various ways to make a dynamic storage
– Fqqlt
Nov 21 at 22:42

When I mean dynamic I mean like I can add elements too it, so I don't know how many elements I am going to be storing initially
– NipIsTrue
Nov 21 at 22:48

@NipIsTrue Then use a std::vector.
– Jesper Juhl
Nov 21 at 22:53

So,you need to use std::vector for that
– Fqqlt
Nov 21 at 22:53

|
show 1 more comment

up vote
-2
down vote

You can allocate storage using new like that:
pigeon *pigeon_array = new pigeon[SIZE]

In SIZE you must enter how many elements do you want to store.But dont forget use delete pigeon_array when u will dont need this array anymore.

Or you can use std::vector or std::array

answered Nov 21 at 22:35

Fqqlt

2

Please don't advocate manual memory management in 2018... "Or you can use std::vector or std::array" - Not or, do!
– Jesper Juhl
Nov 21 at 22:38

I am don't advocate manual memory management I want to show various ways to make a dynamic storage
– Fqqlt
Nov 21 at 22:42

When I mean dynamic I mean like I can add elements too it, so I don't know how many elements I am going to be storing initially
– NipIsTrue
Nov 21 at 22:48

@NipIsTrue Then use a std::vector.
– Jesper Juhl
Nov 21 at 22:53

So,you need to use std::vector for that
– Fqqlt
Nov 21 at 22:53

|
show 1 more comment

up vote
-2
down vote

You can allocate storage using new like that:
pigeon *pigeon_array = new pigeon[SIZE]

In SIZE you must enter how many elements do you want to store.But dont forget use delete pigeon_array when u will dont need this array anymore.

Or you can use std::vector or std::array

answered Nov 21 at 22:35

Fqqlt

You can allocate storage using new like that:
pigeon *pigeon_array = new pigeon[SIZE]

In SIZE you must enter how many elements do you want to store.But dont forget use delete pigeon_array when u will dont need this array anymore.

Or you can use std::vector or std::array

answered Nov 21 at 22:35

Fqqlt

answered Nov 21 at 22:35

Fqqlt

answered Nov 21 at 22:35

Fqqlt

answered Nov 21 at 22:35

Fqqlt

2

Please don't advocate manual memory management in 2018... "Or you can use std::vector or std::array" - Not or, do!
– Jesper Juhl
Nov 21 at 22:38

I am don't advocate manual memory management I want to show various ways to make a dynamic storage
– Fqqlt
Nov 21 at 22:42

When I mean dynamic I mean like I can add elements too it, so I don't know how many elements I am going to be storing initially
– NipIsTrue
Nov 21 at 22:48

@NipIsTrue Then use a std::vector.
– Jesper Juhl
Nov 21 at 22:53

So,you need to use std::vector for that
– Fqqlt
Nov 21 at 22:53

|
show 1 more comment

2

Please don't advocate manual memory management in 2018... "Or you can use std::vector or std::array" - Not or, do!
– Jesper Juhl
Nov 21 at 22:38

I am don't advocate manual memory management I want to show various ways to make a dynamic storage
– Fqqlt
Nov 21 at 22:42

When I mean dynamic I mean like I can add elements too it, so I don't know how many elements I am going to be storing initially
– NipIsTrue
Nov 21 at 22:48

@NipIsTrue Then use a std::vector.
– Jesper Juhl
Nov 21 at 22:53

So,you need to use std::vector for that
– Fqqlt
Nov 21 at 22:53

Please don't advocate manual memory management in 2018... "Or you can use std::vector or std::array" - Not or, do!
– Jesper Juhl
Nov 21 at 22:38

I am don't advocate manual memory management I want to show various ways to make a dynamic storage
– Fqqlt
Nov 21 at 22:42

When I mean dynamic I mean like I can add elements too it, so I don't know how many elements I am going to be storing initially
– NipIsTrue
Nov 21 at 22:48

@NipIsTrue Then use a std::vector.
– Jesper Juhl
Nov 21 at 22:53

So,you need to use std::vector for that
– Fqqlt
Nov 21 at 22:53

|
show 1 more comment

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