delete[] operator

[G1vDizwU]

Hi,
Please have a look at the snip-code below:

double* f1();
vector<double>* f2();

void fct() 
{
  double* f1_data = f1();
  vector<double>* f2_data = f2();
  // Process
  delete[] f1_data;
  delete f2_data;
}

I think the last two lines should be this way:

 delete f1_data;
 delete[] f2_data;

Do you agree?

[mike9407]

Maybe correct.

[helios]

The original code may be correct as it is. Judging from the context, f1() is returning a pointer to an array of doubles. Arrays returned by new[] should be freed by delete[]. f2() appears to be returning a pointer to a single vector, which may contain many doubles. A single vector, regardless of how many elements it contains, should be deleted with delete if it was allocated by new.

Your suggestion would only be correct if f1() returns a pointer to a single double and f2() returns a pointer to an array of vectors of doubles, which I think is less likely.

[G1vDizwU]

Thank you helios,

Would you please complete the f1() and f2() functions' bodies. That way the issue will be solved well. :)

[helios]

For example,

double *f1(){
    double *ret = new double[10];
    for (int i = 0; i < 10; i++)
        ret[i] = M_PI * i;
    return ret;
}

std::vector<double> *f2(){
    std::vector<double> *ret = new std::vector<double>(10);
    for (int i = 0; i < 10; i++)
        (*ret)[i] = M_PI * i;
    return ret;
}

[G1vDizwU]

Thanks.

What if the highest value of f2 is in the third element ([3]) and we have a double* f_high and want to save that third element into that f_high? what code would we use for that please?