main()
{
    int n,a[50],key,opn,i,pos;
    do
    {
        clrscr();
        printf(" \n\n Press 1 -> Binary Search , 2-> Towers of Hanoi 3-> Quit\n");
        scanf("%d",&opn);
        switch(opn)
        {
        case 1: printf(" How Many Elements?");
            scanf("%d",&n);
            printf(" Read all the elements is ASC order \n");
            for(i=1;i<=n;i++)
                scanf("%d",&a[i]);
            printf(" Read the Key Element\n");
            scanf("%d",&key);
            pos=BS(a,key,1,n);
            if(pos)	 printf(" Success: %d found at %d \n", key,pos);
            else	 printf(" Falure: %d Not found in the list ! \n",key);
            break;
        case 2: printf("\n\n How Many Disks ?");
            scanf("%d", &n);
            printf("\n\n Result of Towers of Hanoi for %d Disks \n",n);
            tower(n,'A','B','C');
            printf("\n\n Note: A-> Source, B-> Intermediate, C-> Destination\n");
            break;
        case 3: printf(" Terminating \n"); break;
        default: printf(" Invalid Option !! Try Again !! \n");
        }
        printf(" Press a Key. . . ");  getch();
    }while(opn != 3);
}
int BS(int a[], int key,int low,int high)
{
    int mid;
    if(low > high) return 0; /* failure */
    else
    {
        mid=(low+high)/2;
        if(a[mid]== key) return mid; /* Success */
        if(key < a[mid]) return(BS(a,key,low,mid-1));
        return(BS(a,key,mid+1,high));
    }
}
tower(int n, char src, char intr, char dst)
{
    if(n > 0)
    {
        tower(n-1,src,dst,intr);
        printf("Move disk %d from %c to %c \n", n,src,dst);
        tower(n-1,intr,src,dst);
    }
}

The post C Program for Binary Search and Towers of Hanoi using Recursion first appeared on Student Projects.

#include 
typedef struct tnode
{
    int data;
    struct tnode *right,*left;
}TNODE;

TNODE *CreateBST(TNODE *, int);
void Inorder(TNODE *);
void Preorder(TNODE *);
void Postorder(TNODE *);
main()
{
    TNODE *root=NULL;		 /* Main Program */
    int opn,elem,n,i;
    do
    {
        clrscr();
        printf("\n ### Binary Search Tree Operations ### \n\n");
        printf("\n Press 1-Creation of BST");
        printf("\n       2-Traverse in Inorder");
        printf("\n       3-Traverse in Preorder");
        printf("\n       4-Traverse in Postorder");
        printf("\n       5-Exit\n");
        printf("\n       Your option ? ");
        scanf("%d",&opn);
        switch(opn)
        {
        case 1: root=NULL;
            printf("\n\nBST for How Many Nodes ?");
            scanf("%d",&n);
            for(i=1;i<=n;i++)
            {
                printf("\nRead the Data for Node %d ?",i);
                scanf("%d",&elem);
                root=CreateBST(root,elem);
            }
            printf("\nBST with %d nodes is ready to Use!!\n",n);
            break;
        case 2: printf("\n BST Traversal in INORDER \n");
            Inorder(root); break;
        case 3: printf("\n BST Traversal in PREORDER \n");
            Preorder(root); break;
        case 4: printf("\n BST Traversal in POSTORDER \n");
            Postorder(root); break;
        case 5: printf("\n\n Terminating \n\n"); break;
        default: printf("\n\nInvalid Option !!! Try Again !! \n\n");
            break;
        }
        printf("\n\n\n\n  Press a Key to Continue . . . ");
        getch();
    }while(opn != 5);
}
TNODE *CreateBST(TNODE *root, int elem)
{
    if(root == NULL)
    {
        root=(TNODE *)malloc(sizeof(TNODE));
        root->left= root->right = NULL;
        root->data=elem;
        return root;
    }
    else
    {
        if( elem < root->data )
            root->left=CreateBST(root->left,elem);
        else
            if( elem > root->data )
                root->right=CreateBST(root->right,elem);
            else
                printf(" Duplicate Element !! Not Allowed !!!");

        return(root);
    }
}
void Inorder(TNODE *root)
{
    if( root != NULL)
    {
        Inorder(root->left);
        printf(" %d ",root->data);
        Inorder(root->right);
    }
}

void Preorder(TNODE *root)
{
    if( root != NULL)
    {
        printf(" %d ",root->data);
        Preorder(root->left);
        Preorder(root->right);
    }
}

void Postorder(TNODE *root)
{
    if( root != NULL)
    {
        Postorder(root->left);
        Postorder(root->right);
        printf(" %d ",root->data);
    }
}

The post C Program for Binary Search Tree Creation and Traversals first appeared on Student Projects.

Logic: The Binary search starts by testing the element at the middle of the array. Let us consider an array ‘a’ with all elements arranged in ascending order. Let low and high are the lower and upper indices of the array ‘a’, respectively. We want to search an item K in it. To do this, we calculate a middle index with the values of low and high, let it be mid. Then we compare if K=a[mid] or not.

If it is true, then search is done. Otherwise, the search is to be repeated on left or right half depending on the K<a[mid] or K>a[mid], respectively. In case of low =high and K a[mid], the search terminates unsuccessfully.

Example 1:

Consider the following elements stored in an array,

Example 2:

Consider the following elements stored in an array,

Program:

#include"stdio.h"
#include"conio.h"
void main()
{
	int a[25], i, n, K, flag = 0, low, high, mid;
	clrscr();
	printf("Enter the number of elementsn");
	scanf("%d", &n);
	printf("Enter the elementsn");
	for(i = 0; i<n; i++)
	{
		scanf("%d",&a[i]);
	}
	printf("Enter the key to be searchedn");
	scanf("%d",&K);
	low = 0;
	high = n - 1;
	while(low <= high)
	{
		mid = (low+high)/2;
		if(a[mid] == K)
		{
			flag = 1;
			break;
		}
		else if(K<a[mid])
			high = mid-1;
		else
			low = mid + 1;
	}
	if(flag == 1)
	{
		printf("Key element is found");
	}
	else
	{
		printf("Key element not found");
	}
	getch();
}

The post Binary Search first appeared on Student Projects.