TheAlgorithms-C-Plus-Plus/search/interpolation_search2.cpp

#include <iostream>
int InterpolationSearch(int A[], int n, int x) {
    int low = 0;
    int high = n - 1;
    while (low <= high) {
        int mid = low + (((high - 1) * (x - A[low])) / (A[high] - A[low]));
        if (x == A[mid])
            return mid;  // Found x, return (exit)
        else if (x < A[mid])
            high = mid - 1;  // X lies before mid
        else
            low = mid + 1;  // x lies after mid
    }
    return -1;
}

int main() {
    int A[] = {2, 4, 5, 7, 13, 14, 15, 23};
    int x = 17;
    int index = InterpolationSearch(
        A, 8, x);  // passed array A inside the InterpolationSearch function
    if (index != -1)
        std::cout << "Number " << x << " is at " << index;
    else
        std::cout << "Number " << x << " not found";
}

// randomly set x bcoz array was defined by us , therefore not reasonable for
// asking input. We could have asked for input if array elements were inputed by
// the user.