Implement Binary Search on Integers / Names Program and Algorithm Computer Science Engineering VTU

BinarySearch

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void main()
{
int a[20],low,mid,high,i,n,k,ch;
char b[20][20],key[20];
printf("1. binary search for integer\n2. Binary search for string/name\n");
printf("Enter your choice:\t");
scanf("%d",&ch);
switch(ch)
{
case 1: /* For integers */
            printf("Enter the number of elements in ascending order \n");
            scanf("%d",&n);
           
            printf("Enter the elements\n");
            for(i = 0 ; i < n ; i++)
                        scanf("%d",&a[i]);
            printf("Enter the element to be searched\n");
            scanf("%d",&k);
            low = 0;
            high = n - 1;
            while(low <= high)
            {
            mid = (low + high)/2;
            if(a[mid] == k)
            {
                        printf("Successful search, element %d found at %d\n",k,mid+1);
                        exit(0);
            }
            else if(k < a[mid])
            {
                        high = mid - 1;
            }
            else
            {
                        low = mid + 1;
            }
            }
            printf("Unsuucessful search\n");
 
            break;
case 2: /* For strings */
            printf("Enter the number of Names\n");
            scanf("%d",&n);
 
            printf("Enter the Names in ascending order \n");
            for(i = 0 ; i < n ; i++)
            scanf("%s",b[i]);
            printf("Enter the Name to be searched\n");
            scanf("%s",key);
            low=0;
            high=n-1;
            while(low <= high)
            {
           
            mid=(low + high)/2;
            if(strcmp(key,b[mid])==0)
            {
                        printf("Successful search, Name  %s found at %d\n",key,mid+1);
                        exit(0);
            }
            else if(strcmp(key,b[mid])<0)
            {
                        high=mid-1;
            }
            else
            {
                        low=mid+1;
            }
            }
            printf("Unsuucessful search\n");
            break;
default: printf("Invalid choice\n");
}
}

BinarySearchalg

Start
Read Choice
If choice is 1 goto step A
Else if choice is 2 goto step B
Else print invalid choice
A:        Read n
             for i = 0 to n – 1
                   read a[i]
             Read key
low = 0, high = n – 1
while ( low<=high)
mid= (low + high)/2
                           if (key == a[mid])
found = 1
goto step C
 else if (key > a[mid])
low = mid+ 1
 else
high = mid – 1
end while
C:         if (found) 
print “element is found at location”  goto D
else
print “element not found” goto D
B:         Read n
             for i = 0 to n – 1
                   read str[i]
             Read key
low = 0, high = n – 1
while (high <= low)
mid= (low + high)/2
c = strcmp(key,str[i])
                           if (c == 0)
found = 1
goto step E
 else if (key > a[mid])
low = mid+ 1
 else
high = mid – 1
end while
E:         if (found) 
print “element is found at location”  goto D
else
print “element not found” goto D
D:        Stop