// portable code to count the number of bits

#include <;stdio.h>

int count(unsigned int x)

{

    int n = 0;

    while (x > 0)

    {

        x = x&;(x-1);

        n = n + 1;

    }

    return n;

}

#include<;stdio.h>

#define SIZE 100

void mergesort(int, int a[]);

int main()

{

    int a[SIZE];

    int i, n;

    printf("No of elements to be sorted:n");

    scanf("%d",&n);

    printf("Enter the elements:n");

    for(i=0;i<n;i++)

    scanf("%d",&;a[i]);

    printf("Unsorted list:n");

    for(i=0;i<n;i++)

    printf("%d",a[i]);

    printf("n");

    mergesort(n, &;a);

    printf("Sorted list:n");

    for(i=0;i<n;i++)

    printf("%d ",a[i]);

    printf("n");

    return 0;

}

void mergesort(int n, int a[])

{

    int n1, n2, i, j, k;

    int a1[n];

    int *a2, *a3;

    for (i=0;i<n;i++)

    a1[i] = a[i];

    if (n%2 == 0)

    n1 = n/2;

    else

    n1 = n/2 + 1;

    n2 = n - n1;

    if (n >; 2)

    {

    mergesort(n1, &;a1);

    mergesort(n2, &;a1[n1]);

    }

    j = k = 0;

    a2 = &a1;

    a3 = &;a1[n1];

    for (i=0;i<n;i++)

    {

    if (k == n2)

    {

        a[i] = *(a2+j);

        j++;

    }

    else if (j == n1)

    {

        a[i] = *(a3+k);

        k++;

    }

    else if(*(a2+j) <;= *(a3+k))

    {

        a[i] = *(a2+j);

        j++;

    }

    else

    {

        a[i] = *(a3+k);

        k++;

    }

    }

}