hamming: inner_product version

cpp/hamming/hamming.cpp

@@ -1,10 +1,24 @@
 #include "hamming.h"
 
+#include <functional>
+#include <numeric>
+#include <stdexcept>
+#include <string>
+
 namespace hamming {
 
-int compute(const char *first, const char *second) {
+using namespace std;
 
-    return 0;
+int compute(const char *cstr1, const char *cstr2) {
+
+    const string str1(cstr1);
+    const string str2(cstr2);
+
+    if (str1.size() != str2.size())
+        throw domain_error("Strings have different length");
+
+    return inner_product(str1.begin(), str1.end(), str2.begin(), 0,
+            plus<int>(), not_equal_to<char>());
 }
 
 }

cpp/hamming/hamming.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#define EXERCISM_RUN_ALL_TESTS
+
 namespace hamming {
 
 int compute(const char *first, const char *second);