Added fibonacci search

search/fibonacci_search.cpp

@@ -0,0 +1,61 @@
+#include <iostream>
+#include <vector>
+
+/*
+Input: a sorted array and a value
+Output: if the array contains the value, returns its index (index of its first occurence)
+        else returns -1
+*/
+
+int fibonacchi_search(std::vector<int> arr, int value){
+    int last = 0, current = 1, offset = -1, index;
+    int length = arr.size();
+    int next = last + current;
+
+    while(next < length){
+        last = current;
+        current = next;
+        next = last + current;
+    }
+
+    while(next > 1){
+        index = std::min(offset + last, length-1);
+        if(arr[index] < value){
+            next = current;
+            current = last;
+            last = next - current;
+            offset = index;
+        } else if(arr[index] > value){
+            next = last;
+            current = current - last;
+            last = next - current;
+        } else {
+            return index;
+        }
+    }
+    if(current && !arr.empty() && arr[offset+1] == value){
+        return offset+1;
+    }
+    return -1;
+}
+
+int main() {
+    int size, value;
+    std::cout << "Enter size of a sorted array: " << std::endl;
+    std::cin >> size;
+    std::cout << "Enter array elements: " << std::endl;
+
+    std::vector<int> arr(size);
+    for(int i = 0; i < size; i++){
+        std::cin >> arr[i];
+    }
+    std::cout << "Enter the value you're looking for: " << std::endl;
+    std::cin >> value;
+    int index = fibonacchi_search(arr, value);
+    if(index != -1){
+        std::cout << "Index of the given value is " << index << std::endl;
+    } else {
+        std::cout << "Array does not contain the value" << std::endl;
+    }
+    return 0;
+}