Interpolation search in C++

Author: Your Name

searchingAlgo/interpolationSearch/interpolationSearch.cpp

@@ -0,0 +1,49 @@
+#include <iostream>
+#include <vector> 
+
+/**
+ * Interpolation search function.
+ * 
+ * @param v Sorted vector on which the search will be performed.
+ * @param x Element to be searched.
+ * @return Element index if found; -1 otherwise.
+ */ 
+int interpolationSearch(const std::vector<long int> &v, long int x) {
+    int lo = 0; // first index
+    int hi = v.size() - 1; // last index
+
+    while(lo <= hi && x >= v[lo] && x <= v[hi]) {
+        if(lo == hi) {
+            if(v[lo] == x) return lo;
+            return -1;
+        }
+
+        // standard algorithm formula
+        // pos is a higher value when the searched element is closer to v[hi]
+        // pos is a lower value when the searched element is closer to v[lo]
+        int pos = lo + (((double)(hi - lo)/(v[hi] - v[lo])) * (x - v[lo]));
+
+        if(v[pos] == x) return pos; // found
+
+        if(v[pos] < x) lo = pos + 1; // x is in upper part
+            else hi = pos - 1; // x is in lower part
+    }
+
+    return -1; // not found
+}
+
+/**
+ * Driver code.
+ */ 
+int main() {
+    // sorted vector on which the search will be performed; [0, 30]
+    std::vector<long int> v = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30};
+    long int x = 7; // element to be searched
+    int index = interpolationSearch(v, x);
+
+    if(index != -1) std::cout << "Element found at index " << index;
+        else std::cout << "Element not found";
+    std::cout << std::endl;
+
+    return 0;
+}