// C Program to shuffle a given array

 

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

 

// A utility function to swap to integers

void swap (int *a, int *b)

{

    int temp = *a;

    *a = *b;

    *b = temp;

}

 

// A utility function to print an array

void printArray (int arr[], int n)

{

    for (int i = 0; i < n; i++)

        printf("%d ", arr[i]);

    printf("\n");

}

 

// A function to generate a random permutation of arr[]

void randomize ( int arr[], int n )

{

    // Use a different seed value so that we don't get same result each time we run this program

    srand ( time(NULL) );

 

    /* Start from the last element and swap one by one. We don't need to run for the first element that's why i > 0 */

    for (int i = n-1; i > 0; i--)

    {

        // Pick a random index from 0 to i

        int j = rand() % (i+1);

 

        // Swap arr[i] with the element at random index

        swap(&arr[i], &arr[j]);

    }

}

 

// Driver program to test above function.

int main()

{

    int arr[] = {1, 2, 3, 4, 5, 6, 7, 8};

    int n = sizeof(arr)/ sizeof(arr[0]);

    randomize (arr, n);

    printArray(arr, n);

 

    return 0;

}