C Online Compiler
Example: Merge Sort with User Input in C
C
C++
C#
Java
Python
PHP
main.c
STDIN
Run
// Merge Sort with User Input #include <stdio.h> #include <stdlib.h> // For malloc and free // Function to merge two sorted subarrays void merge(int arr[], int left, int mid, int right) { int i, j, k; int n1 = mid - left + 1; int n2 = right - mid; // Create temporary arrays int *L = (int *)malloc(n1 * sizeof(int)); int *R = (int *)malloc(n2 * sizeof(int)); // Copy data to temp arrays L[] and R[] for (i = 0; i < n1; i++) L[i] = arr[left + i]; for (j = 0; j < n2; j++) R[j] = arr[mid + 1 + j]; // Merge the temp arrays back into arr[left..right] i = 0; // Initial index of first subarray j = 0; // Initial index of second subarray k = left; // 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++; } // Free the dynamically allocated temporary arrays free(L); free(R); } // Function to implement Merge Sort void mergeSort(int arr[], int left, int right) { if (left < right) { // Find the middle point int mid = left + (right - left) / 2; // Sort first and second halves mergeSort(arr, left, mid); mergeSort(arr, mid + 1, right); // Merge the sorted halves merge(arr, left, mid, right); } } // 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() { // Step 1: Declare variables for array size and pointer int size; int *arr; // Step 2: Get array size from user printf("Enter the number of elements: "); scanf("%d", &size); // Step 3: Dynamically allocate memory for the array arr = (int *)malloc(size * sizeof(int)); if (arr == NULL) { printf("Memory allocation failed!\n"); return 1; // Indicate an error } // Step 4: Get array elements from user printf("Enter %d integers:\n", size); for (int i = 0; i < size; i++) { printf("Element %d: ", i + 1); scanf("%d", &arr[i]); } // Step 5: Print the original array printf("Original array: "); printArray(arr, size); // Step 6: Call mergeSort to sort the array mergeSort(arr, 0, size - 1); // Step 7: Print the sorted array printf("Sorted array: "); printArray(arr, size); // Step 8: Free the dynamically allocated memory free(arr); return 0; }
Output
Clear
ADVERTISEMENTS