Thread: Recursive Rotate Left

an exercise;
I want to write a recursive function that rotates left an integer array, i.e. the given array
1 2 3 4
will be
2 3 4 1
after the function executed.
for this I write

Code:

#include <iostream>
#include <iomanip>
using namespace std;
int vArray[] = {1,2,3,4,5,6,7,8,9};
const int vsize = 9;
void rotateLeft(int foo[], int size) {
	if ( foo[1] == NULL )
		foo[0] = *(foo - size);
	else{
		foo[0] = foo[1];
		rotateLeft(&foo[1], --size);
	}
}
int main() {
	rotateLeft(vArray, vsize);
	cout << "Element" << setw( 13 ) << "Value" << endl;
	for(int i=0; i<vsize; ++i)
		cout << setw( 7 ) << i << setw( 13 ) << vArray[ i ] << endl;
	return 0;
}

But i couldn't handle with the base condition I think. Actually this code gives

Code:

Element        Value
      0            2
      1            3
      2            4
      3            5
      4            6
      5            7
      6            8
      7            9
      8            9

How can i take the value of first element and equalize the value of last element to it?

I need a recursive function, not iterative or not a loop

The recursive function would need three pieces of information:
the array,
the array size,
the current position in the array

I can think of a couple different methods:
Swap element n and element n+1 until n+1 > size
make a copy of element and put it into element n-1 working backwards from the end

yes!
why couldn't i think of it, swapping two adjacent elements would work,
Thanks Thantos,
I will try this solution and post it here.

And the solution is

Code:

#include <iostream>
#include <iomanip>
using namespace std;
int vArray[] = {1,2,3,4,5,6,7,8,9};
const int vsize = 9;
void rotateLeft(int foo[], int size) {
	int temp;
	if (size == 1);
	else{
		temp = foo[0];
		foo[0] = foo[1];
		foo[1] = temp;
		rotateLeft(&foo[1], --size);
	}
}
int main() {
	rotateLeft(vArray, vsize);
	cout << "Element" << setw( 13 ) << "Value" << endl;
	for(int i=0; i<vsize; ++i)
		cout << setw( 7 ) << i << setw( 13 ) << vArray[ i ] << endl;
	return 0;
}