How to initialize 2d object array of strucuture.

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but when i access the attributes of Structure i get the exception, the code i used is below

What I have tried:

i have structure name "Guitar", code that is used to create 2 D array of Guitar Objects

C++

Guitar ** guitarlists = (Guitar **)malloc(sizeof(Guitar *));
 for (int i = 0; i < row; i++)
 {
     guitarlists[i] = (Guitar *)malloc(sizeof(Guitar));
 }

Posted 17-May-18 0:41am

Umer Farooq

Updated 17-May-18 3:25am

KarstenK

v2

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3 solutions

Solution 1

Quote:
Guitar ** guitarlists = (Guitar **)malloc(sizeof(Guitar *));

That should be

C

Guitar ** guitarlists = (Guitar **)malloc(row * sizeof(Guitar *));

[update]
As Thaddeus Jones correctly pointed out, if you need a bidimensional array of Guitar then you have to modify

Quote:
guitarlists[i] = (Guitar *)malloc(sizeof(Guitar));

as well.
[/update]

Please note: since you apparently are using C++, why don't you use C++ programming language and standard library features (e.g. containers)?

Posted 17-May-18 0:58am

CPallini

Updated 17-May-18 1:20am

v2

Solution 3

In C++ it is standard to use the "new" new and delete operators like that:

C++

Guitar *guitarlists = new Guitar[row];//normal array
delete guitarlists;

Or am I missing some bits?

Posted 17-May-18 3:26am

KarstenK

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User 7429338 · Accepted Answer · 2018-05-17T01:00:00

Solution 2

If you want a 2D array of r rows and c columns, you can do this:

Guitar ** guitarlists = (Guitar **)malloc(r* sizeof(Guitar *));
for (int i = 0; i < r; i++)
{
	guitarlists[i] = (Guitar *)malloc(c * sizeof(Guitar));
}

Posted 17-May-18 1:00am

User 7429338

Comments

CPallini 17-May-18 7:16am

Damn, I have to update my solution. :-)
5.