//A->array, l->left most index, r->right most indexMERGE-SORT(A, l, r)//function named “MERGE-SORT” to sort the array “A”, with the lower bound “l” and upper bound “r” and splits the array later into two parts.    if  l < r        mid = (l+(r-l)/2)    MERGE-SORT(A, l, mid)// Function call keeps on splitting the left part of the array till single element is achieved.    MERGE-SORT (A, mid+1, r)// Function call keeps on splitting the right part of the array till single element is achieved..    MERGE(A, l, mid ,r)end funcMERGE(A, l, mid, r)    nL = mid-l+1 //nL tells the max number of elements in the array L    nR = r-mid //nR tells the max number of elements in the array R    Create arrays L[1..nL+1] and R[1..nR+1]    for  i=0 to nL-1        L[i] = A[l+i]   end for    for j=0 to nR-1 // adds elements to the initial array A        R[j] = A[m+l+j]    end for    i=0;  j=0;  k=l;    while  i < nL and j < nR  // adds elements to the initial array A        if  L[i] <= R[j]            A[k]=L[i];  i=i+1;  k=k+1;        else            A[k]=R[j];  j=j+1;  k=k+1;    end while    while  i < nL  // adds elements to the initial array A        A[k]=L[i];  i=i+1;  k=k+1;    end while    while  j < nR  // adds elements to the initial array A        A[k]=R[j];  j=j+1;  k=k+1;    end whileend func

#include<stdlib.h> #include<stdio.h> // Merges two subarrays of arr[ ]. // First subarray is arr[l..m] // Second subarray is arr[m+1..r] void merge(int arr[ ], int l, int m, int r) {     int i, j, k;     int n1 = m - l + 1;     int n2 = r - m;     /* create temp 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 there     are any */    while (i < n1)     {         arr[k] = L[i];         i++;         k++;     }     /* Copy the remaining elements of R[], if there     are any */    while (j < n2)     {         arr[k] = R[j];         j++;         k++;     } } /* l is for left index and r is right index of the sub-array of arr to be sorted */void mergeSort(int arr[], int l, int r) {     if (l < r)     {         // Same as (l+r)/2, but avoids overflow for         // large l and h         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);     } } /* UTILITY FUNCTIONS *//* Function to print an array */void printArray(int A[ ], int size) {     int i;     for (i=0; i < size; i++)         printf("%d ", A[i]);     printf("\n"); } /* Driver program to test above functions */int main() {     int arr[] = {12, 11, 13, 5, 6, 7}; // or you can take input direct from the user itself using scanf function    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; }