Practical 3
Aim - : Write a program to sort a array by using merge and quick sort in c language.
Quick Sort
#include <stdio.h>
#include <stdio.h>
// Function to swap two elements
void swap(int* a, int* b) {
int temp = *a;
*a = *b;
*b = temp;
// Partition function
int partition(int arr[], int low, int high) {
int pivot = arr[high]; // Pivot element
int i = (low - 1); // Index of smaller element
for (int j = low; j <= high - 1; j++) {
// If current element is smaller than or equal to the pivot
if (arr[j] <= pivot) {
i++; // Increment index of smaller element
swap(&arr[i], &arr[j]);
swap(&arr[i + 1], &arr[high]);
return (i + 1);
// QuickSort function
void quickSort(int arr[], int low, int high) {
if (low < high) {
// Partitioning index
int pi = partition(arr, low, high);
// Separately sort elements before and after partition
quickSort(arr, low, pi - 1);
quickSort(arr, pi + 1, high);
// Function to print an array
void printArray(int arr[], int size) {
for (int i = 0; i < size; i++)
printf("%d ", arr[i]);
printf("\n");
int main() {
int arr[] = {3, 8, 4, 1, 9, 2};
int n = sizeof(arr) / sizeof(arr[0]);
quickSort(arr, 0, n - 1);
printf("Sorted array: \n");
printArray(arr, n);
return 0;
}
Merge sort :
#include <stdio.h>
// Function to merge two subarrays of arr[]
void merge(int arr[], int l, int m, int r) {
int i, j, k;
int n1 = m - l + 1;
int n2 = r - m;
// Create temporary arrays
int L[n1], R[n2];
// Copy data to temp arrays L[] and R[]
for (i = 0; i < n1; i++)
L[i] = arr[l + i];
for (j = 0; j < n2; j++)
R[j] = arr[m + 1 + j];
// Merge the temp arrays back into arr[l..r]
i = 0; // Initial index of first subarray
j = 0; // Initial index of second subarray
k = l; // Initial index of merged subarray
while (i < n1 && j < n2) {
if (L[i] <= R[j]) {
arr[k] = L[i];
i++;
} else {
arr[k] = R[j];
j++;
k++;
}
// Copy the remaining elements of L[], if any
while (i < n1) {
arr[k] = L[i];
i++;
k++;
// Copy the remaining elements of R[], if any
while (j < n2) {
arr[k] = R[j];
j++;
k++;
// MergeSort function
void mergeSort(int arr[], int l, int r) {
if (l < r) {
int m = l + (r - l) / 2;
// Sort first and second halves
mergeSort(arr, l, m);
mergeSort(arr, m + 1, r);
merge(arr, l, m, r);
// Function to print an array
void printArray(int arr[], int size) {
for (int i = 0; i < size; i++)
printf("%d ", arr[i]);
printf("\n");
}
int main() {
int arr[] = {15, 7, 3, 20, 10, 5};
int arr_size = sizeof(arr) / sizeof(arr[0]);
printf("Given array is \n");
printArray(arr, arr_size);
mergeSort(arr, 0, arr_size - 1);
printf("\nSorted array is \n");
printArray(arr, arr_size);
return 0;
