Swap arrays by using pointers in C++

Question

I have two arrays of pointers to doubles that I need to swap. Rather than just copy the data within the arrays, it would be more efficient just to swap the pointers to the arrays. I was always under the impression that array names were essentially just pointers, but the following code receives a compiler error:

double left[] = {1,2,3};
double right[] = {9,8,7};

double * swap = left;
left = right; // Error "ISO C++ forbids assignment of arrays"
right = swap; // Error "incompatible types in assignment of `double*' to `double[((unsigned int)((int)numParameters))]'"

Creating the arrays dynamically would solve the problem, but can't be done in my application. How do I make this work?

Answer 1

double array_one[] = {1,2,3};
double array_two[] = {9,8,7};

double *left = array_one;
double *right = array_two;

double * swap = left;
left = right;
right = swap;

Works nicely.

edit: The definitions array_one and array_two shouldn't be used and the doubleleft and doubleright should be as public as your original left and right definitions.

Answer 2

Arrays are not the same as pointers and cannot be swapped in the way you describe. To do the pointer swap trick, you must use pointers, either dynamically allocate the memory, or use pointers to access the data (in the way Daniel has described).