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:

Binary Search recursive program.

Binary Search is a program where in the input array is sorted i.e., ascending order in this case. Every time the array is split into two parts and the middle element is compared with the key element to be searched.

Source Code:

 #include <stdio.h>  
 #include <stdlib.h>  
 int bin_srch(int a[], int n, int key, int low, int high)  
 {  
     int mid;  
     if(low <= high)  
    {  
         mid = (low + high)/2;  
         if(a[mid] == key)  
         {  
             return mid;  
          }  
          else if(key < a[mid])  
         {  
             return bin_srch(a, n, key, low, mid-1);  
          }  
          else if(key > a[mid])  
         {  
             return bin_srch(a, n, key, mid+1, high);  
          }  
     }  
     else  
     {  
          return -1;  
     }  
 }  
 int main()  
 {  
     int a[10], n, key, low, mid, high, i, indx;  
     printf("\nEnter size of array: ");  
     scanf("%d", &n);  
     printf("\nEnter elements of array: ");  
     for(i=0;i<n;i++)  
     {  
          scanf("%d", &a[i]);  
     }  
     printf("\nEnter the key element to be searched: ");  
     scanf("%d", &key);  
     low = 0;  
     high = n-1;  
     indx = bin_srch(a, n, key, low, high);  
     if(indx == -1)  
     {  
          printf("\nSearch unsuccessful");  
      }  
      else  
      {  
          printf("\nElement found at position %d\n\n", indx+1);  
      }  
 }