CODEWITHSUNDEEP
c++searchbinary
roadgh1256
roadgh1256

Reputation: 1

why is my binary search not not working with my array?

trying to learn some basic data structures and algorithms and ive tried to code a basic binary search but it doesn't work unless the input is the same as the middle? can anyone help?

void Search(int input) {

    int array[10] = { 0.1,2,3,4,5,6,7,8,9,10 };
    int first = array[0];
    int last = sizeof(array) / sizeof(array[0]);;
    int middle = first + last / 2;

    if (input == middle) {
        cout << "search succesful";
    }
    else if (input > middle) {
        middle + 1;
        Search(input);

    }
    else if (input < middle) {
        middle - 1;
        Search(input);

    }
}

  int main()
    {
     int input;
     cin >> input;
     Search(input);
    }

Upvotes: 0

Views: 200

Answers (1)

AsKreY
AsKreY

Reputation: 63

If you want to use recursion than you should also pass the right and left border of array and change them in your if statements. When you do middle-1 you don't change anything. Here is binary search implemantation

int binarySearch(int nums[], int low, int high, int target)
{
    // Base condition (search space is exhausted)
    if (low > high) {
        return -1;
    }
 
    // find the mid-value in the search space and
    // compares it with the target
 
    int mid = (low + high)/2;    // overflow can happen
    // int mid = low + (high - low)/2;
 
    // Base condition (target value is found)
    if (target == nums[mid]) {
        return mid;
    }
 
    // discard all elements in the right search space,
    // including the middle element
    else if (target < nums[mid]) {
        return binarySearch(nums, low, mid - 1, target);
    }
 
    // discard all elements in the left search space,
    // including the middle element
    else {
        return binarySearch(nums, mid + 1, high, target);
    }
}

Upvotes: 5

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