Free Memory

[aeo3]

Hi All,
I have a simple question. about free memery, I feel this is one of many reasons that make the memory crashing.
if we have the following array

 
x=new float*[n];
if(x=NULL)
{
exit(1);
}
for(int i=0;i<n;i++)
{
   x[i]=new float[4];
  if(x[i]=NULL)
   {
      exit(1);
    }
 x[i][0]=0;
x[i][1]=0;
x[i][2]=0;
x[i][3]=0;
}
 

My question is the following code will free all memory reserved? I think there is something missing

for(int i=0;i<n;i++)
{
     delete x[i];
}
delete [] x;
 

Thanks in advance

[Meetee]

Hi All,
I have a simple question. about free memery, I feel this is one of many reasons that make the memory crashing.
if we have the following array

 
x=new float*[n];
if(x=NULL)
{
exit(1);
}
for(int i=0;i<n;i++)
{
   x[i]=new float[4];
  if(x[i]=NULL)
   {
      exit(1);
    }
 x[i][0]=0;
x[i][1]=0;
x[i][2]=0;
x[i][3]=0;
}
 

My question is the following code will free all memory reserved? I think there is something missing

for(int i=0;i<n;i++)
{
     delete x[i];
}
delete [] x;
 

Thanks in advance

Hi,

delete x[i] is suffiecient to free memory. Don't use delete [] x;

Regards

[shankhs]

I think you are assigning memory to a pointer which stores the memory space of array of pointers................isnt it so?
To delete it I think you have done it correct.

[aeo3]

What I am talking about, I reserved a space for the array x and another space for each x[i], but in x[i] there is a space for 4 floats, What I am worried about is that space for 4 floats, In my opinion I didnot free memory for this space.

[abhisoni]

Hi,

Basically here x is a 2Dimensional array. Memory of a 2d array can be freed completely by just freeing x []. There 'll be no memory loss.

[weaknessforcats]

Memory of a 2d array can be freed completely by just freeing x []. There 'll be no memory loss.

Not so. A delete [] deletes the array. If the array elements are pointers, destructors are not called since pointers don't have destructors.

class Data
{
public:
    ~Data() {cout << "dtor" << endl;}
};
int main()
{
   Data** array = new Data*[2];
   array[0] = new Data;
   array[1] = new Data;
   delete [] array;    //Data destrcutors not called.
}
 

You have to delete each element and then delete the array.