# C Program for Program for array rotation

• Last Updated : 01 Jun, 2021

Write a function rotate(ar[], d, n) that rotates arr[] of size n by d elements.

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Rotation of the above array by 2 will make array

METHOD 1 (Using temp array)

```Input arr[] = [1, 2, 3, 4, 5, 6, 7], d = 2, n =7
1) Store d elements in a temp array
temp[] = [1, 2]
2) Shift rest of the arr[]
arr[] = [3, 4, 5, 6, 7, 6, 7]
3) Store back the d elements
arr[] = [3, 4, 5, 6, 7, 1, 2]```

## C++

 `// C++ program to rotate an array by ``// d elements``#include ``using` `namespace` `std;`` ` `int` `main(){``    ``int` `a[]={1,2,3,4,5,6,7,8,9};``    ``int` `n=9;``    ``int` `d=2;``    ``int` `temp[d];``    ``for``(``int` `i=0;i
Output:
```345678912
```

Time complexity : O(n)
Auxiliary Space : O(d)

METHOD 2 (Rotate one by one)

```leftRotate(arr[], d, n)
start
For i = 0 to i < d
Left rotate all elements of arr[] by one
end```

To rotate by one, store arr[0] in a temporary variable temp, move arr[1] to arr[0], arr[2] to arr[1] â€¦and finally temp to arr[n-1]
Let us take the same example arr[] = [1, 2, 3, 4, 5, 6, 7], d = 2
Rotate arr[] by one 2 times
We get [2, 3, 4, 5, 6, 7, 1] after first rotation and [ 3, 4, 5, 6, 7, 1, 2] after second rotation.

## C++

 `// C++ program to rotate an array by ``// d elements``#include ``using` `namespace` `std;`` ` `/*Function to left Rotate arr[] of ``  ``size n by 1*/``void` `leftRotatebyOne(``int` `arr[], ``int` `n)``{``   ``int` `temp = arr[0];``   ``int` `i;``   ``for``(i = 0; i < n-1; i++)``   ``arr[i] = arr[i+1];``    ` `   ``arr[i] = temp;``}`` ` `/*Function to left rotate arr[] of size n by d*/``void` `leftRotate(``int` `arr[], ``int` `d, ``int` `n)``{``    ``for` `(``int` `i = 0; i < d; i++)``    ``leftRotatebyOne(arr, n);``}`` ` `/* utility function to print an array */``void` `printArray(``int` `arr[], ``int` `size)``{``    ``for``(``int` `i = 0; i < size; i++)``    ``cout << arr[i] << ``" "``;``}`` ` `/* Driver program to test above functions */``int` `main()``{``   ``int` `arr[] = {1, 2, 3, 4, 5, 6, 7};``   ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]);``    ` `   ``// Function calling``   ``leftRotate(arr, 2, n);``   ``printArray(arr, n);`` ` `   ``return` `0;``}`

## C

 `/*Function to left Rotate arr[] of size n by 1*/``void` `leftRotatebyOne(``int` `arr[], ``int` `n);`` ` `/*Function to left rotate arr[] of size n by d*/``void` `leftRotate(``int` `arr[], ``int` `d, ``int` `n)``{``  ``int` `i;``  ``for` `(i = 0; i < d; i++)``    ``leftRotatebyOne(arr, n);``}`` ` `void` `leftRotatebyOne(``int` `arr[], ``int` `n)``{``  ``int` `i, temp;``  ``temp = arr[0];``  ``for` `(i = 0; i < n-1; i++)``     ``arr[i] = arr[i+1];``  ``arr[i] = temp;``}`` ` `/* utility function to print an array */``void` `printArray(``int` `arr[], ``int` `size)``{``  ``int` `i;``  ``for``(i = 0; i < size; i++)``    ``printf``(``"%d "``, arr[i]);``}`` ` `/* Driver program to test above functions */``int` `main()``{``   ``int` `arr[] = {1, 2, 3, 4, 5, 6, 7};``   ``leftRotate(arr, 2, 7);``   ``printArray(arr, 7);``   ``getchar``();``   ``return` `0;``}`

## C#

 `// C# program for array rotation``using` `System;`` ` `class` `GFG``{``    ``/* Function to left rotate arr[]``    ``of size n by d*/``    ``static` `void` `leftRotate(``int` `[]arr, ``int` `d,``                                     ``int` `n) ``    ``{``        ``for` `(``int` `i = 0; i < d; i++)``            ``leftRotatebyOne(arr, n);``    ``}`` ` `    ``static` `void` `leftRotatebyOne(``int` `[]arr, ``int` `n) ``    ``{``        ``int` `i, temp = arr[0];``        ``for` `(i = 0; i < n - 1; i++)``            ``arr[i] = arr[i + 1];``             ` `        ``arr[i] = temp;``    ``}`` ` `    ``/* utility function to print an array */``    ``static` `void` `printArray(``int` `[]arr, ``int` `size) ``    ``{``        ``for` `(``int` `i = 0; i < size; i++)``            ``Console.Write(arr[i] + ``" "``);``    ``}`` ` `    ``// Driver code``    ``public` `static` `void` `Main() ``    ``{``        ``int` `[]arr = {1, 2, 3, 4, 5, 6, 7};``        ``leftRotate(arr, 2, 7);``        ``printArray(arr, 7);``    ``}``}`` ` `// This code is contributed by Sam007`
Output:
```3 4 5 6 7 1 2
```

Output :

`3 4 5 6 7 1 2 `

Time complexity : O(n * d)
Auxiliary Space : O(1)

METHOD 3 (A Juggling Algorithm)
This is an extension of method 2. Instead of moving one by one, divide the array in different sets
where number of sets is equal to GCD of n and d and move the elements within sets.
If GCD is 1 as is for the above example array (n = 7 and d =2), then elements will be moved within one set only, we just start with temp = arr[0] and keep moving arr[I+d] to arr[I] and finally store temp at the right place.
Here is an example for n =12 and d = 3. GCD is 3 and Let arr[] be {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}

a) Elements are first moved in first set â€“
(See below diagram for this movement)

arr[] after this step –> {4 2 3 7 5 6 10 8 9 1 11 12}

b) Then in second set.
arr[] after this step –> {4 5 3 7 8 6 10 11 9 1 2 12}

c) Finally in third set.
arr[] after this step –> {4 5 6 7 8 9 10 11 12 1 2 3}

## C++

 `// C++ program to rotate an array by ``// d elements``#include ``using` `namespace` `std;`` ` `/*Function to get gcd of a and b*/``int` `gcd(``int` `a,``int` `b)``{``    ``if``(b == 0)``    ``return` `a;``     ` `    ``else``    ``return` `gcd(b, a%b);``}`` ` `/*Function to left rotate arr[] of siz n by d*/``void` `leftRotate(``int` `arr[], ``int` `d, ``int` `n)``{``  ``for` `(``int` `i = 0; i < gcd(d, n); i++)``  ``{``    ``/* move i-th values of blocks */``    ``int` `temp = arr[i];``    ``int` `j = i;``     ` `    ``while``(1)``    ``{``      ``int` `k = j + d;``      ``if` `(k >= n)``        ``k = k - n;``         ` `      ``if` `(k == i)``        ``break``;``         ` `      ``arr[j] = arr[k];``      ``j = k;``    ``}``    ``arr[j] = temp;``  ``}``}`` ` `// Function to print an array ``void` `printArray(``int` `arr[], ``int` `size)``{``    ``for``(``int` `i = 0; i < size; i++)``    ``cout << arr[i] << ``" "``;``}`` ` `/* Driver program to test above functions */``int` `main()``{``   ``int` `arr[] = {1, 2, 3, 4, 5, 6, 7};``   ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]);``    ` `   ``// Function calling``   ``leftRotate(arr, 2, n);``   ``printArray(arr, n);`` ` `   ``return` `0;``}`

## C

 `/* function to print an array */``void` `printArray(``int` `arr[], ``int` `size);`` ` `/*Function to get gcd of a and b*/``int` `gcd(``int` `a,``int` `b);`` ` `/*Function to left rotate arr[] of siz n by d*/``void` `leftRotate(``int` `arr[], ``int` `d, ``int` `n)``{``  ``int` `i, j, k, temp;``  ``for` `(i = 0; i < gcd(d, n); i++)``  ``{``    ``/* move i-th values of blocks */``    ``temp = arr[i];``    ``j = i;``    ``while``(1)``    ``{``      ``k = j + d;``      ``if` `(k >= n)``        ``k = k - n;``      ``if` `(k == i)``        ``break``;``      ``arr[j] = arr[k];``      ``j = k;``    ``}``    ``arr[j] = temp;``  ``}``}`` ` `/*UTILITY FUNCTIONS*/``/* function to print an array */``void` `printArray(``int` `arr[], ``int` `size)``{``  ``int` `i;``  ``for``(i = 0; i < size; i++)``    ``printf``(``"%d "``, arr[i]);``}`` ` `/*Function to get gcd of a and b*/``int` `gcd(``int` `a,``int` `b)``{``   ``if``(b==0)``     ``return` `a;``   ``else``     ``return` `gcd(b, a%b);``}`` ` `/* Driver program to test above functions */``int` `main()``{``   ``int` `arr[] = {1, 2, 3, 4, 5, 6, 7};``   ``leftRotate(arr, 2, 7);``   ``printArray(arr, 7);``   ``getchar``();``   ``return` `0;``}`

## C#

 `// C# program for array rotation``using` `System;`` ` `class` `GFG``{``    ``/* Function to left rotate arr[] ``    ``of size n by d*/``    ``static` `void` `leftRotate(``int` `[]arr, ``int` `d, ``                                     ``int` `n) ``    ``{``        ``int` `i, j, k, temp;``        ``for` `(i = 0; i < gcd(d, n); i++) ``        ``{``            ``/* move i-th values of blocks */``            ``temp = arr[i];``            ``j = i;``            ``while` `(``true``) ``            ``{``                ``k = j + d;``                ``if` `(k >= n) ``                    ``k = k - n;``                ``if` `(k == i) ``                    ``break``;``                ``arr[j] = arr[k];``                ``j = k;``            ``}``            ``arr[j] = temp;``        ``}``    ``}`` ` `    ``/*UTILITY FUNCTIONS*/``    ``/* Function to print an array */``    ``static` `void` `printArray(``int` `[]arr, ``int` `size) ``    ``{``        ``for` `(``int` `i = 0; i < size; i++)``            ``Console.Write(arr[i] + ``" "``);``    ``}`` ` `    ``/* Function to get gcd of a and b*/``    ``static` `int` `gcd(``int` `a, ``int` `b) ``    ``{``        ``if` `(b == 0)``            ``return` `a;``        ``else``            ``return` `gcd(b, a % b);``    ``}`` ` `    ``// Driver code``    ``public` `static` `void` `Main() ``    ``{``        ``int` `[]arr = {1, 2, 3, 4, 5, 6, 7};``        ``leftRotate(arr, 2, 7);``        ``printArray(arr, 7);``    ``}``}`` ` `// This code is contributed by Sam007`
Output:
```3 4 5 6 7 1 2
```

Output :

`3 4 5 6 7 1 2 `

Time complexity : O(n)
Auxiliary Space : O(1)
Please refer complete article on Program for array rotation for more details!

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