Question

#include <iostream>

using namespace std;

bool binarySearch(int arr[], int start, int end, int target){

//your code here

}

void fill(int arr[], int count){

for(int i = 0; i < count; i++){

cout << "Enter number: ";

cin >> arr[i];

} }

void display(int arr[], int count){ for(int i = 0; i < count; i++){

cout << arr[i] << endl;

} }

int main() {

cout << "How many items: ";

int count;

cin >> count;

int * arr = new int[count];

fill(arr, count);

int target;

cout << "Enter item to try to find: ";

cin >> target;

bool found = binarySearch(arr, 0, count-1, target);

if(found){ cout << "Item Found" << endl;

} else{ cout << "Item Not Found" << endl;

} }

Answer 1

#include <iostream>

using namespace std;

bool binarySearch(int arr[], int start, int end, int target) {
    if (start <= end) {
        int mid = (start + end) / 2;
        if (arr[mid] == target) {
            return true;
        } else if (target < arr[mid]) {
            return binarySearch(arr, start, mid - 1, target);
        } else {
            return binarySearch(arr, mid + 1, end, target);
        }
    }
    return false;
}

void fill(int arr[], int count) {
    for (int i = 0; i < count; i++) {
        cout << "Enter number: ";
        cin >> arr[i];
    }
}

void display(int arr[], int count) {
    for (int i = 0; i < count; i++) {
        cout << arr[i] << endl;
    }
}

int main() {
    cout << "How many items: ";
    int count;
    cin >> count;
    int *arr = new int[count];
    fill(arr, count);
    int target;
    cout << "Enter item to try to find: ";
    cin >> target;
    bool found = binarySearch(arr, 0, count - 1, target);
    if (found) {
        cout << "Item Found" << endl;
    } else {
        cout << "Item Not Found" << endl;
    }
}

Answer 2

// Binary Search in C++

#include <iostream>
using namespace std;

int binarySearch(int array[], int x, int low, int high) {
  
	// Repeat until the pointers low and high meet each other
  while (low <= high) {
    int mid = low + (high - low) / 2;

    if (array[mid] == x)
      return mid;

    if (array[mid] < x)
      low = mid + 1;

    else
      high = mid - 1;
  }

  return -1;
}

int main(void) {
  int array[] = {3, 4, 5, 6, 7, 8, 9};
  int x = 4;
  int n = sizeof(array) / sizeof(array[0]);
  int result = binarySearch(array, x, 0, n - 1);
  if (result == -1)
    printf("Not found");
  else
    printf("Element is found at index %d", result);
}