impls/bsearch.cpp


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/* bsearch.cpp
 * Created: 2023-07-10
 * Author: Aryadev Chavali
 */

#include <algorithm>
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <string>
#include <vector>

using std::cin;
using std::cout;
using std::endl;
using std::ostream;
using std::string;
using std::vector;

vector<int> arr;

ostream &print_arr(ostream &os)
{
  os << "[";
  for (size_t i = 0; i < arr.size(); ++i)
    os << arr[i] << (i == arr.size() - 1 ? "" : ",");
  return os << "]";
}

int bsearch(int n, int l = 0, int u = arr.size() - 1)
{
  int midpoint = ((u + l) / 2);
  if (l >= u || u <= 0)
    return -1;
  int val = arr[midpoint];
  if (val == n)
    return midpoint;
  else if (val > n)
    return bsearch(n, l, midpoint - 1);
  else
    return bsearch(n, midpoint + 1, u);
}

int main(void)
{
  std::ifstream input("bsearch.txt");
  string line;
  while (std::getline(input, line))
    arr.push_back(std::stoi(line));
  std::sort(std::begin(arr), std::end(arr));
  string inp;
  cout << "Enter number to search: ";
  cin >> inp;
  int to_search = std::stoi(inp);
  cout << bsearch(to_search) << endl;
  return 0;
}