Question

Please use C language to code all of the problems below. Please submit a .c file for each of the solutions, that includes the required functions, tests you wrote to check your code and a main function to run the code.

Q2. Implement the quick-sort algorithm.

Answer 1

C CODE :

#include<stdio.h>

int partition (int a[], int down, int up)
{
   int pivot = a[up]; // pivot element
   int i = (down - 1);

   for (int j = down; j <= up- 1; j++)
   {
       if (a[j] < pivot)
       {
           i++;
           int temp = a[i];
           a[i] = a[j];
           a[j] = temp;
       }
   }
   int temp1 = a[i + 1];
   a[i + 1] = a[up];
   a[up] = temp1;
   return (i + 1);
}

void sort(int a[], int down, int up)
{
   if (down < up)
   {
       int pivot = partition(a, down, up); // call partition
       sort(a, down, pivot - 1); // recursive function for left hand of array
       sort(a, pivot + 1, up); // recursive function for right hand of array
   }
}

int main()
{
int n;
printf("Enter the size of the array : ");
scanf("%d", &n); // read the array size
   int a[n];
   printf("Enter the array elements : ");
   for(int i = 0; i < n; i++)
   {
   scanf("%d", &a[i]); // read the array elements
   }
  
   sort(a, 0, n - 1); // call the sort function
   printf("After sorting the array : ");
   for (int i = 0; i < n; i++)
   {
       printf("%d ", a[i]); // print the array after sorting
   }
   return 0;
}

OUTPUT :