Question

Apply mergesort algorithm to sort S, O, R, T, I, N, G in alphabetical order.

Answer 1

Note: For any doubts please put a comment before giving a thumbs down.

Code:

#include<stdio.h>

#include<stdlib.h>

#include<string.h> //To use the string functions like strcmp and strcpy

#define MAX 10

  // This is the default size of every string

void Merge(char* arr[],int low,int mid,int high) //Merging the Array Function

{

    int nL= mid-low+1;

    int nR= high-mid;

    char** L=malloc(sizeof(char *)*nL);

    char** R=malloc(sizeof(char *)*nR);

    int i;

    for(i=0;i<nL;i++)

    {

        L[i]=malloc(sizeof(arr[low+i]));

        strcpy(L[i],arr[low+i]);

    }

    for(i=0;i<nR;i++)

    {

        R[i]=malloc(sizeof(arr[mid+i+1]));

        strcpy(R[i],arr[mid+i+1]);

    }

    int j=0,k;

    i=0;

    k=low;

    while(i<nL&&j<nR)

    {

        if(strcmp(L[i],R[j])<0)strcpy(arr[k++],L[i++]);

        else strcpy(arr[k++],R[j++]);

    }

    while(i<nL)strcpy(arr[k++],L[i++]);

    while(j<nR)strcpy(arr[k++],R[j++]);

}

void MergeSort(char* arr[],int low,int high) //Main MergeSort function

{

    if(low<high)

    {

        int mid=(low+high)/2;

        MergeSort(arr,low,mid);

        MergeSort(arr,mid+1,high);

        Merge(arr,low,mid,high);

    }

}

int main()

{

    printf("\nEnter the size of the array desired: ");

    int size;  //This is the String array size

    scanf("%d",&size);

    char** arr= malloc(sizeof(char *)* size); //Creating required string array

    printf("\nEnter the strings of the array: ");

    *arr = "SORTING";

    int i;

    MergeSort(arr,0,size-1);

    printf("\nThe Sorted Array is: ");

    for(i=0;i<size;i++)printf("%s ->",arr[i]);

    return 0;

}