diff --git a/cpp/phone-number/phone_number.cpp b/cpp/phone-number/phone_number.cpp
index 2e7adac..35785b3 100644
--- a/cpp/phone-number/phone_number.cpp
+++ b/cpp/phone-number/phone_number.cpp
@@ -1,13 +1,33 @@
 #include "phone_number.h"
 
 #include <algorithm>
-#include <ctype>
+#include <cctype>
 
 using namespace std;
 
+static const int number_size     = 10;
+static const int area_code_size  = 3;
+static const int first_part_size = 3;
+
+static const char invalid_number[] = "0000000000";
+
+
 phone_number::phone_number(const string &str)
 {
-    static const string invalid_number = "0000000000";
+    number_.resize(str.size());
+    string::iterator iter = copy_if(str.cbegin(), str.cend(),
+            number_.begin(), static_cast<int (*)(int)>(isdigit));
+    number_.resize(distance(number_.begin(), iter));
+
+    if (number_.size() == number_size + 1 && number_.front() == '1') {
+
+        number_.erase(number_.begin());
+    }
+
+    if (number_.size() != number_size) {
+
+        number_ = invalid_number;
+    }
 }
 
 string phone_number::number() const
@@ -17,10 +37,13 @@ string phone_number::number() const
 
 string phone_number::area_code() const
 {
-    return area_code_;
+    return number_.substr(0, area_code_size);
 }
 
 phone_number::operator string() const
 {
-    return number_;
+    return string("(") + area_code() + ") "
+        + number_.substr(area_code_size, first_part_size)
+        + '-'
+        + number_.substr(area_code_size + first_part_size, string::npos);
 }
diff --git a/cpp/phone-number/phone_number.h b/cpp/phone-number/phone_number.h
index f18f51b..599f766 100644
--- a/cpp/phone-number/phone_number.h
+++ b/cpp/phone-number/phone_number.h
@@ -1,10 +1,11 @@
 #pragma once
 
+#define EXERCISM_RUN_ALL_TESTS
+
 #include <string>
 
 class phone_number
 {
-    std::string area_code_;
     std::string number_;
 
 public: