Swapping contiguous layers in 3d array

[Anton]

Hi guys
I'm really new to C++, so I don't quite get connection between arrays and pointers and how to use it in elegant way. Anyway, I have a 3d array, with four layers filled with 1s,2s,3s and 4s respectively. It's declaration is as follows: double dArray[4][3][3]. And what I need to do is to swap contiguous layers. Could anyone give me any hint? And why can't I perform following assignment: dArray[i]=dArray[i+1];? I get the

'=' : left operand must be l-value

compiler error, but I don't understand why and what it means in this context.

[Bazzy]

You can't assign arrays, you need to access each single element or use STL containers

[BettyBoopTS]

you cant copy arrays like that, here is an example of one way to copy the contents of one array to another:
EDIT: yes, this would be the 'access each single element' approach Bazzy is referring to.

#include <iostream>
using namespace std;

int main()
{
	int a;
	int array1[10] = {1,2,3,4,5,6,7,8,9,10};
	int array2[10] = {0,0,0,0,0,0,0,0,0,0};
	
	cout << "\n\n";

	cout << "array1: ";
	for(a=0;a<=9;a++)  cout << array1[a] << " ";
	
	cout << "\n\n";
	
	cout << "array2: ";
	for(a=0;a<=9;a++)  cout << array2[a] << " ";
	
	cout << "\n\n";
	
	for(a=0;a<=9;a++) array2[a] = array1[a];// copying contents of array1 to array2
	
	cout << "array1: ";
	for(a=0;a<=9;a++)  cout << array1[a] << " ";
	
	cout << "\n\n";
	
	cout << "array2: ";
	for(a=0;a<=9;a++)  cout << array2[a] << " ";

	return 0;
}

array1: 1 2 3 4 5 6 7 8 9 10

array2: 0 0 0 0 0 0 0 0 0 0 

array1: 1 2 3 4 5 6 7 8 9 10

array2: 1 2 3 4 5 6 7 8 9 10

[wasabi]

Obviously, if you're going to be making switches and not just copies, you'll need a temporary place-holder to save the values of array2 before they get replaced by array1's so that you can replace array1 with array2's values.

[BettyBoopTS]

true, you could work this sort of logic into your programming:

temporary array = array1
array1=array2
array2=temporary array

[IOwnTheWeb]

Obviously, if you're going to be making switches and not just copies, you'll need a temporary place-holder to save the values of array2 before they get replaced by array1's so that you can replace array1 with array2's values.

True. An example of that is as follows:

int a, b, c;
int main()
{
a = 20;
b = 25;
swap(&a,&b);
}

void swap(int &a, int &b)
{
c = a;
a = b;
b = a;
} 

i'm not sure if my syntax is exactly correct. I've been playing in java & just switched back over.

& if you need to do it with an array, I suggest you use a for loop.