Binary-Search.cpp

//Searches a number in an array using binary search technique

#include<iostream>
using namespace std;

int main() {
  int n, i, arr[50], search, first, last, middle;
  
  cout << "Enter total number of elements :";
  cin >> n;
  cout << "Enter "<< n << " numbers :";
  
  for (i=0; i<n; i++) {
    cin >> arr[i];
  }
  
  cout << "Enter a number to find :";
  cin >> search;
  
  first = 0;
  last = n-1;
  middle = (first+last)/2;
  
  while (first <= last) {
    if(arr[middle] < search) {
      first = middle + 1;
    }
    else if(arr[middle] == search) {
      cout << search << " found at location " << middle+1 << "\n";
      break;
    }
    else {
      last = middle - 1;
    }
    middle = (first + last)/2;
  }
  
  if(first > last) {
    cout << "Not found! " << search << " is not present in the list.";
  }
}