Binary Search

Algorithm

BinarySearch()
Begin
	Read array size, "size"
	Declare start = 0
	Declare stop = size - 1
	Declare index = -1
	Declare arr[size]
	for (i = 0; i < size; i++), do
		Read element and store in arr[i]
	End For
	Read element to search and store it in "target"
	while (start <= stop), do
		Set mid = (start + stop) / 2
		if (arr[mid] < target), then
			Set start = mid + 1
		else if (arr[mid] > target), do
			Set stop = mid - 1
		else
			Set index = mid
			break
		End If
	End While
	if (index == -1), then
		Display "Element not found"
	else 
		Display "Element found at position " + (index + 1)
	End If
End

Program

#include <stdio.h>

int main() {
  int i, size, target, mid, index = -1;
  printf("Enter the size of the array: ");
  scanf("%d", &size);

  int start = 0, end = size - 1;

  // Create the array
  int arr[size];
  for (i = 0; i < size; i++) {
    printf("Enter element %d: ", i + 1);
    scanf("%d", &arr[i]);
  }

  // Enter element to search
  printf("Enter element to search: ");
  scanf("%d", &target);

  while (start <= end) {
    mid = (end + start) / 2;

    if (arr[mid] == target) {
      index = mid;
      break;
    } else if (arr[mid] < target) {
      start = mid + 1;
    } else {
      end = mid - 1;
    }
  }

  if (index == -1) {
    printf("Element not found");
  } else {
    printf("Element found at position %d", index + 1);
  }

  return 0;
}