Data Structure Array: Program for array rotation

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <stack>
#include <string>
#include <fstream>
#include <map>
using namespace std;

int gcd(int a, int b) {
return b == 0? a : gcd(b, a % b);
}

void leftrotate(int arr[], int d, int n) {
for (int i = 0; i < gcd(d, n); i++) {
int tmp = arr[i];
int j = i;
while (1) {
int k = j + d;
if (k >= n) k -= n;
if (k == i) break;
arr[j] = arr[k];
j = k;
}
arr[j] = tmp;
}
}

int main() {
int arr[7] = {1, 2, 3, 4, 5, 6, 7};
leftrotate(arr, 2, 7);
for (int i = 0; i < 7; i++) cout << arr[i] << " ";
return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <stack>
#include <string>
#include <fstream>
#include <map>
using namespace std;

void reverse(int arr[], int a, int b) {
for (int i = 0; i < (b-a)/2; i++) swap(arr[a+i], arr[b-1-i]);
}

void leftrotate(int arr[], int d, int n) {
reverse(arr, 0, d);
reverse(arr, d, n);
reverse(arr, 0, n);
}

int main() {
int arr[7] = {1, 2, 3, 4, 5, 6, 7};
leftrotate(arr, 2, 7);
for (int i = 0; i < 7; i++) cout << arr[i] << " ";
return 0;
}