Given a sorted list of elements, if an element you’re looking for is in that list, binary search returns the position where it’s located. Otherwise, binary search returns null.

Computational Complexity: log2  N

#include <stdio.h>
int binarySearch(int list[], int high, int number) {
  int low = 0;

  while (low <= high) {
    int middle = (low + high) / 2;

    if (list[middle] == number) {
      return middle;
    }

    if (list[middle] < number) {
      low = middle + 1;
    } else {
      high = middle - 1;
    }
  }
  return -1;
}

## binarySearch({1, 5, 3, 2}, 3, 2) => position 3
## binarySearch({1, 5, 3, 2}, 3, 8) => -1