Binary search begins by finding the middle element of
the set and comparing it with the key value. If key value is smaller than
middle element, it means all elements from middle element to last element of
the set are greater than key value, so they must not be searched and should be
discarded. So now the new set should comprise of elements from first to element
just before middle element. If key value is greater than middle element, it
means all elements from first element to middle element of the set are smaller
than key value, so they must not be searched and should be discarded. So now
new set should comprise of elements from first element after middle element to last
element. If key value is equal to middle element, then index of middle element
is returned.
//Iterative binary search in C using
function
#include
<stdio.h>
int
main()
{
int array[] = {9,10,12,15,32,50};
int key = 17,arraySize=0,i,result=-1;
//function declaration
int binarySearch(int array[],int n,int
value);
//finding the size(no of elements) of array
arraySize = sizeof(array)/ sizeof(int);
//function calling
result=binarySearch(array,arraySize,key);
if(result!=-1)
printf("Element %d found at
position %d.\n",key,result+1);
else
printf("Element %d does not
exist.\n",key);
return 0;
}
//function
definition
int binarySearch(int array[],int n,int
value){
int
index=-1,i,first,last,mid;
first=0;
last=n-1;
while(first<=last)
{
mid=(first+last)/2;//index of middle
element
if(value<array[mid])
{
last=mid-1;
}
else if(value>array[mid])
first=mid+1;
else{
index=mid;
break;
}
Output: key=10;
Output: key=32;
Please comment if you find anything incorrect, or you want to improve the topic discussed above.
