C++ error when defining array

Question

Im trying to declare an array in C++ but i keep getting this error.

error C2440: 'initializing' : cannot convert from 'int *' to 'int []'

for this line

int b[] = new int[elements];

Full Code

int* reverseArray (int a[] ,int elements)
{
    int *pointer;
    int x= elements-1;
    int b[] = new int[elements];
    pointer=b[];
    for (int i= 0; i < elements; i++)
    {
        b[i] = a[x--];
    }
    return pointer;
}

You are asking for a memory leak even if you fix the allocation and swapping of values. Instead consider using std::vector<int> — AJG85
– AJG85, Commented May 3, 2012 at 23:23

James Custer · Accepted Answer · 2012-05-03 23:37:16Z

9

new returns a pointer, so you should change

int b[] = new int[elements];

to

int* b = new int[elements];

and you should just remove pointer and simply return b, so

int* reverseArray (int a[] ,int elements)
{
  int x = elements-1;
  int* b = new int[elements];
  for (int i = 0; i < elements; ++i)
    b[i] = a[x--];
  return b;
}

But you should really consider using std::vector. If you use a std::vector, to reverse the array, you can simply use std::reverse from <algorithm>.

edited May 3, 2012 at 23:37

answered May 3, 2012 at 23:19

James Custer

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4 Comments

Antarr Byrd Over a year ago

for pointer = b it throws cannot convert from 'int *[]' to 'int *'

Antarr Byrd Over a year ago

i'm not allowed to use vectors...class assignment

James Custer Over a year ago

@atbyrd In that case, keep them in mind for the future. I added a bit to my answer.

Ed Swangren Over a year ago

@atbyrd: You didn't read carefully. You wrote int *b[], which is an array of pointers to int. new returns a pointer! You need to declare b as int *b;

Ed Heal · Accepted Answer · 2012-05-03 23:20:31Z

0

Use vectors - lot easier to use

answered May 3, 2012 at 23:20

Ed Heal

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7 Comments

Ed Swangren Over a year ago

Ok, but this doesn't help a beginner understand anything, so -1. Understanding concepts is far more useful than being told to use a library (of course, he should use a vector, but that is tangential to the problem at hand).

Ed Heal Over a year ago

I cannot put verbatim into the library. Just would not like to put that person that that person can achieve a lot more by using a library. I would have not quarrel or contempt if they want to ask any question.

Ed Swangren Over a year ago

Ok, I just don't think this is a useful answer for a beginner.

Ed Heal Over a year ago

@EdS. - I did give a link to the appropriate web site so that person can learn STL.

lesderid Over a year ago

Very true, but this should be a comment (which someone else already posted), not an answer.

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