Delete a dynamic array but keep a pointer

问题

I have made a function for expanding array, and this function is inside a class.

Because this function creates new_arr and copies all the numbers of array into the new_arr and at the end sets pointer of array with new_arr, I wold like to know how to delete numbers in array becuse I dont need it any more

void Array::bigger() {
    int  new_size = size * 2;
    int *new_arr = new int[new_size];
    for (int f1=0; f1<last; f1++) {
        new_arr[f1] = array[f1];
    }
    this->size = new_size;
    array = new_arr;
}

Thanks

回答1:

Assuming this is an exercise, then delete the array before re-assigning to the new one:

delete [] array;
array = new_arr;

In real code, use an std::vector<int> instead of the dynamically allocated array.

回答2:

free memory before lose pointer to it:

void Array::bigger() {
    int  new_size = size * 2;
    int *new_arr = new int[new_size];
    for (int f1=0; f1<last; f1++) {
        new_arr[f1] = array[f1];
    }
    this->size = new_size;
    delete[] array; //free memory
    array = new_arr;
}

来源：https://stackoverflow.com/questions/13415572/delete-a-dynamic-array-but-keep-a-pointer