Answer to Question #193980 in C++ for Akash

Question

Explain the Binary search approach for the following elements to search 7 in the array list. 2,4,13,45,87,100 write the logical part of the program also.

Answer 1

Binary search is the search technique which works efficiently on the sorted lists. Hence, in order to search an element into some list by using binary search technique, we must ensure that the list is sorted.

Binary search follows divide and conquer approach in which, the list is divided into two halves and the item is compared with the middle element of the list. If the match is found then, the location of middle element is returned otherwise, we search into either of the halves depending upon the result produced through the match.

code for given problem.

#include<iostream>
using namespace std;
int searching(int arr[], int l, int r, int x){
  if(r>=l){
    int mid=l+(r-l)/2;
    if(arr[mid]==x)
      return mid+1;
    if(arr[mid]>x)
      return searching(arr,l,mid-1,x);
    return searching(arr,mid+1,r,x);
  }
  return -1;
}
int main(void){
  int arr[]={2,4,13,45,87,100};
  int x=7;
  int n=sizeof(arr)/sizeof(arr[0]);
  int result= searching(arr,0,n-1,x);
  (result==-1) ? cout<<"given element in not present in array"
                    :cout<<"Element is present at index"<<result;
  return 0;
}