Dynamic structure array inside dynamic structure?

[lindsey laho]

How could I put a dynamic structure inside of a structure using only the <new> and <iostream> libraries?
This post is similar to my previous one:
http://www.cplusplus.com/forum/beginner/56039/

However the answer wasn't what I thought it was instead of getting a dynamic structure inside of a dynamic structure I just got a dynamic structure that contained a structure.

So how would this work?

#include<iostream>
using namespace std;

struct fruit{
char name[50];
double weight, volume, calories;
bool poisonous;
};

struct container{
fruit * fruits;
double weight, volume;
};


int main(){
int some_number_determined_later_in_code;
int another_number_determined_later_in_code;
container * containers = new(nothrow) containers [some_number_determined_later_in_code];
containters.fruits = new (nothrow) fruit[int another_number_determined_later_in_code;];
cout<<"Thanks for solving the problem";
system ("pause");
return 0;
}

Is the way that I've formulated it even remotely correct?

By the way this code has been typed by memory and not tested, so there's probably bugs...

[hamsterman]

If 'containers' is an array, address its elements with containers[x].fruits = ...
If containers was a single element, you'd write containers->fruits = ...
The rest seems good.

[lindsey laho]

All the structures are dynamic arrays.
could someone test this?
I'm not using my own computer (it doesn't have internet) to write this.
Right now i don't have a way to transfer this code to my home pc, so i'll need someone else to test...

[hamsterman]

There is http://ideone.com/

[bbgst]

That is correct. Remember you have to delete them when you're done.

But you could also use std::vector instead of using dynamic arrays.

[lindsey laho]

I don't understand how to use vector, so i'll just keep using struct. =)
Thanks for the link hamsterman.
When i compile a slightly fixed version of the code there i get the errors:

prog.cpp: In function ‘int main()’:
prog.cpp:21: error: expected type-specifier before ‘containers’
prog.cpp:21: error: cannot convert ‘int*’ to ‘container*’ in initialization
prog.cpp:21: error: expected ‘,’ or ‘;’ before ‘containers’
prog.cpp:22: error: ‘containters’ was not declared in this scope
prog.cpp:21: warning: unused variable ‘containers’

could someone tell me why this isn't working?
I've tried a couple of different methods.... but no luck.

new version of code:

#include<iostream>
using namespace std;
 
struct fruit{
char name[50];
double weight, volume, calories;
bool poisonous;
};
 
struct container{
fruit * fruits;
double weight, volume;
};
 
 
int main(){
int some_number_determined_later_in_code;
int another_number_determined_later_in_code;
some_number_determined_later_in_code= 3;    //just added this to get rid of an error.
another_number_determined_later_in_code=2;  //just added this to get rid of an error.
container * containers = new(nothrow) containers [some_number_determined_later_in_code];
containters.fruits = new (nothrow) fruit[another_number_determined_later_in_code];
cout<<"Thanks for solving the problem";
//system ("pause");
return 0;
}

[hamsterman]

new containers should be new container

containters.fruits should be containters->fruits

By the way, in the future, use [code] tags, instead of [output].

[lindsey laho]

okay, I don't want to seem dumb, nevertheless i'm still having problems compiling it.
I want to get it correct in case someone comes back to look at this later.

#include<iostream>
using namespace std;
 
struct fruit{
char name[50];
double weight, volume, calories;
bool poisonous;
};
 
struct container{
fruit * fruits;
double weight, volume;
};
 
 
int main(){
int some_number_determined_later_in_code;
int another_number_determined_later_in_code;
some_number_determined_later_in_code= 3;    //just added this to get rid of an error.
another_number_determined_later_in_code=2;  //just added this to get rid of an error.
container * containers = new(nothrow) container [some_number_determined_later_in_code];
containters->fruits = new (nothrow) fruit[another_number_determined_later_in_code];
cout<<"Thanks for solving the problem";
//system ("pause");
return 0;
}

now gives the errors:

prog.cpp: In function ‘int main()’:
prog.cpp:22: error: ‘containters’ was not declared in this scope
prog.cpp:21: warning: unused variable ‘containers’

[naraku9333]

container * containers = new(nothrow) container [some_number_determined_later_in_code];
//containers is an array, you need to iterate through and new each index of containers
for(int i = 0; i< some_number_determined_later_in_code; ++i){
containters[i]->fruits = new (nothrow) fruit[another_number_determined_later_in_code];
}

[hamsterman]

You wrote "containters".
Also, naraku is (almost) right. You need a for loop here. You want to initialize all allocated elements. Though if containers is a pointer, containers[i] is an object and . should be used instead of -> to access its members.

[naraku9333]

@hamsterman
Nice catch, that's what I get for copy/pasting.

[lindsey laho]

Here's the final code that works:
If you're reading this you can ignore all previous versions of code.

#include<iostream>
using namespace std;

struct fruit{
char name[50];
double weight, volume, calories;
bool poisonous;
};

struct container{
fruit * fruits;
double weight, volume;
};

int main(){
int some_number_determined_later_in_code;
int another_number_determined_later_in_code;
some_number_determined_later_in_code= 3;    //just added this to get rid of an error.
another_number_determined_later_in_code=2;  //just added this to get rid of an error.
container * containers = new(nothrow) container [some_number_determined_later_in_code];

for(int i = 0; i< some_number_determined_later_in_code; ++i){
	containers[i].fruits = new (nothrow) fruit[another_number_determined_later_in_code];
}
cout<<"Finally Done!";
system ("pause");
return 0;
}

Special Thanks to:
hamsterman
naraku9333
and
bbst

Without you the coding process would've screeched to a halt.