Sorting Techniques in C

 Sorting Methods : 

1.     bubble sort
2.   insertion sort
3.  merge sort
4.   quick sort

1) bubble sort program in c

  #include <stdio.h>

void bubble_sort(long [], long);

int main()
{
  long array[100], n, c;

  printf("Enter number of elements\n");
  scanf("%ld", &n);

  printf("Enter %ld integers\n", n);

  for (c = 0; c < n; c++)
    scanf("%ld", &array[c]);

  bubble_sort(array, n);

  printf("Sorted list in ascending order:\n");

  for (c = 0; c < n; c++)
     printf("%ld\n", array[c]);

  return 0;
}

void bubble_sort(long list[], long n)
{
  long c, d, t;

  for (c = 0 ; c < n - 1; c++) {
    for (d = 0 ; d < n - c - 1; d++) {
      if (list[d] > list[d+1]) {
        /* Swapping */
        t         = list[d];
        list[d]   = list[d+1];
        list[d+1] = t;
      }
    }
  }
}

The output of this C program will depend on the input provided by the user. Here's an example of how the program would execute with sample input:

mathematica
Enter number of elements
6

Enter 6 integers

45
12
78
32
61
19 
Sorted list in ascending order: 
12
19
32
45
61
78

2) insertion sort

/* Insertion sort ascending order */

#include <stdio.h>

int main()
{
  int n, array[1000], c, d, t, flag = 0;

  printf("Enter number of elements\n");
  scanf("%d", &n);

  printf("Enter %d integers\n", n);

  for (c = 0; c < n; c++)
    scanf("%d", &array[c]);

  for (c = 1 ; c <= n - 1; c++) {
    t = array[c];

    for (d = c - 1 ; d >= 0; d--) {
      if (array[d] > t) {
        array[d+1] = array[d];
        flag = 1;
      }
      else
        break;
    }
    if (flag)
      array[d+1] = t;
  }

  printf("Sorted list in ascending order:\n");

  for (c = 0; c <= n - 1; c++) {
    printf("%d\n", array[c]);
  }

  return 0;
}

The output of this C program will depend on the input provided by the user. Here's an example of how the program would execute with sample input:

mathematica
Enter number of elements
6 
Enter 6 integers
45
12
78
32
61
19

Sorted list in ascending order:

12
19
32
45
61
78

3) merge sort program in c

#include<stdio.h>

void mergesort(int a[],int l,int r);

void merge(int a[],int l1,int r1,int l2,int r2);

int main() {

 int a[30],n,l;

 printf("Enter number of elements:");

 scanf("%d",&n);

 printf("Enter array elements:");

 for(l=0;l<n;l++)

   scanf("%d",&a[l]);

   mergesort(a,0,n-1);

   printf("\nSorted array is :");

   for(l=0;l<n;l++)

     printf("%d ",a[l]);

     return 0;

}

void mergesort(int a[],int l,int r) {

 int mid;

 if(l<r) {

   mid=(l+r)/2;

   mergesort(a,l,mid); //left recursion

   mergesort(a,mid+1,r); //right recursion

   merge(a,l,mid,mid+1,r); //merging of two sorted sub-arrays

 }

}

void merge(int a[],int l1,int r1,int l2,int r2) {

 int temp[50]; //array used for merging

 int l,r,k;

 l=l1; //beginning of the first list

 r=l2; //beginning of the second list

 k=0;

 while(l<=r1 && r<=r2) //while elements in both lists {

   if(a[l]<a[r])

      temp[k++]=a[l++];

   else

      temp[k++]=a[r++];

}

 while(l<=r1) //copy remaining elements of the first list

   temp[k++]=a[l++];

   while(r<=r2) //copy remaining elements of the second list

     temp[k++]=a[r++];

     //Transfer elements from temp[] back to a[]

     for(l=l1,r=0;l<=r2;l++,r++)

       a[l]=temp[r];

}

Here's an example of what the output might look like:

yaml
Enter number of elements: 5 
Enter array elements: 12 5 7 18 3 
Sorted array is: 3 5 7 12 18

4) Quick sort program in c 

/*

 * C Program to sort an array of integers using Quick Sort without recursion

 */

 

#include <stdio.h>

#include <stdlib.h>

 

int quickSort(int *arr, int low, int high)

{

    int i = low, j = high;

    int pivot = arr[(low + high) / 2];

    while (i <= j)

    {

        while (arr[i] < pivot)

            i++;

        while (arr[j] > pivot)

            j--;

        if (i <= j)

        {

            int temp = arr[i];

            arr[i] = arr[j];

            arr[j] = temp;

            i++;

            j--;

        }

    }

    if (low < j)

        quickSort(arr, low, j);

    if (i < high)

        quickSort(arr, i, high);

    return 0;

}

 

int main(void)

{

    puts("Enter the number of elements in the array: ");

    int n;

    scanf("%d", &n);

    int arr[n];

    puts("Enter the elements of the array: ");

    for (int i = 0; i < n; i++)

    {

        printf("arr[%d]: ", i);

        scanf("%d", &arr[i]);

    }

    int low = 0;

    int high = n - 1;

    int pivot = arr[high];

    int k = low - 1;

    for (int j = low; j < high; j++)

    {

        if (arr[j] <= pivot)

        {

            k++;

            int temp = arr[k];

            arr[k] = arr[j];

            arr[j] = temp;

        }

    }

    int temp = arr[k + 1];

    arr[k + 1] = arr[high];

    arr[high] = temp;

    int pi = k + 1;

    quickSort(arr, low, pi - 1);

    quickSort(arr, pi + 1, high);

    puts("The sorted array is: ");

    for (int i = 0; i < n; i++)

    {

        printf("%d ", arr[i]);

    }

    return 0;

}

Here's an example of what the output might look like:

less
Enter the number of elements in the array: 5 
Enter the elements of the array:
arr[0]: 12
arr[1]: 5
arr[2]: 7
arr[3]: 18
arr[4]: 3 
The sorted array is:
3 5 7 12 18