Merge-sort for sorting elements in ascending order.

Merge-sort:

It is a sorting technique that sequences data by continuously merging items in the list. Every single item in the original unordered list is merged with another, creating groups of two. Every two-item group is merged, creating groups of four and so on until there is one ordered list.

Source Code:

 #include <stdio.h>  
 #include <stdlib.h>  
 int c[50];  
 void merge(int b[], int low,int mid,int high)  
 {  
     int i, j, k=low;  
     i = low;  
     j = mid+1;  
     while((i <= mid) && (j <= high))   //Comparing & inserting items in new ordered list  
     {  
         if(b[i] <= b[j])  
             c[k++] = b[i++];  
         else  
             c[k++] = b[j++];  
     }  
     while(i <= mid)        //Inserting remaining items from 1st half in new list  
         c[k++] = b[i++];  
     while(j <= high)       //Inserting remaining items from 2nd half in new list  
         c[k++] = b[j++];  
     for(k=low;k<=high;k++)  
         b[k] = c[k];  
 }  
 void mergesort(int a[], int low, int high)  
 {  
     int mid;  
     if(low<high)  
     {  
         mid = (low+high)/2;  
         mergesort(a,low,mid);           //Dividing the list into two - 1st half  
         mergesort(a,mid+1,high);         // 2nd half  
         merge(a,low,mid,high);          //Merging the lists  
     }  
 }  
 int main()  
 {  
     int a[50], i, n;  
     double e,s,t;  
     printf("\nEnter the size of the array: ");  
     scanf("%d", &n);  
     srand(time(NULL));  
     for(i=1;i<=n;i++)  
         a[i] = rand()%50 +1;  
     printf("\nElements of the array are: ");  
     for(i=1;i<=n;i++)  
         printf("%d ", a[i]);  
     mergesort(a,1,n);  
     printf("\nThe sorted array is: ");  
     for(i=1;i<=n;i++)  
         printf("%d ", c[i]);  
 }  

Sample Output: