Binary search on k-rotated array

rotated_binary_search.cpp

#include <iostream>

int at(int* arr, int n, int k, int m) {
    return arr[((m + (n - (k % n))) % n)];
}

int rotated_binary_search(int* arr, int n, int k, int key) {
    int low = 0, high = n-1, mid, v;
    
    while (low <= high) {
        mid = low + (high - low)/2;
        v = at(arr, n, k, mid + k);
        
        if (v < key)
            low = mid + 1;
        else if (v > key)
            high = mid - 1;
        else
            return (mid + k) % n;
    }
    return -1;
}

void runBinarySearch(int* arr, int n, int k, int key) {
    char c = '\n';
    std::cout << "Original:\n";
    for (int i = 0; i < 2*n; ++i) {
        if (i < n) std::cout << "(" << i << ") ";
        else {
            std::cout << c << " " << arr[i % n];
            c = ' ';
        }
    }
    std::cout << '\n';
    c = '\n';
    std::cout << "\nAfter " << k << " rotation(s):\n";
    for (int i = 0; i < 2*n; ++i) {
        if (i < n) std::cout << "(" << i << ") ";
        else {
            std::cout << c << " " << at(arr, n, k, i % n);
            c = ' ';
        }
    }
    std::cout << '\n';
    std::cout << "\nSearch for " << key << " gives: " << rotated_binary_search(arr, n, k, key) << '\n';
}

int main() {
    int arr[] = {5, 12, 22, 32, 59, 60, 63, 72, 101, 1024};
    int n = sizeof(arr)/sizeof(int);
    int key = 1024;
    runBinarySearch(arr, n, 2, key);
}