1 files changed, 77 insertions, 0 deletions
diff --git a/src/boost/libs/contract/example/features/private_protected.cpp b/src/boost/libs/contract/example/features/private_protected.cpp
new file mode 100644
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--- /dev/null
+++ b/src/boost/libs/contract/example/features/private_protected.cpp
@@ -0,0 +1,77 @@
+
+// Copyright (C) 2008-2018 Lorenzo Caminiti
+// Distributed under the Boost Software License, Version 1.0 (see accompanying
+// file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt).
+// See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
+
+#include <boost/contract.hpp>
+#include <limits>
+#include <cassert>
+
+//[private_protected
+class counter {
+protected: // Protected functions use `function()` (like non-members).
+    void set(int n) {
+        boost::contract::check c = boost::contract::function()
+            .precondition([&] {
+                BOOST_CONTRACT_ASSERT(n <= 0);
+            })
+            .postcondition([&] {
+                BOOST_CONTRACT_ASSERT(get() == n);
+            })
+        ;
+
+        n_ = n;
+    }
+
+private: // Private functions use `function()` (like non-members).
+    void dec() {
+        boost::contract::old_ptr<int> old_get = BOOST_CONTRACT_OLDOF(get());
+        boost::contract::check c = boost::contract::function()
+            .precondition([&] {
+                BOOST_CONTRACT_ASSERT(
+                        get() + 1 >= std::numeric_limits<int>::min());
+            })
+            .postcondition([&] {
+                BOOST_CONTRACT_ASSERT(get() == *old_get - 1);
+            })
+        ;
+
+        set(get() - 1);
+    }
+    
+    int n_;
+    
+    /* ... */
+//]
+
+public:
+    int get() const {
+        int result;
+        boost::contract::check c = boost::contract::public_function(this)
+            .postcondition([&] {
+                BOOST_CONTRACT_ASSERT(result <= 0);
+                BOOST_CONTRACT_ASSERT(result == n_);
+            })
+        ;
+
+        return result = n_;
+    }
+
+    counter() : n_(0) {} // Should contract constructor and destructor too.
+    
+    void invariant() const {
+        BOOST_CONTRACT_ASSERT(get() <= 0);
+    }
+
+    friend int main();
+};
+
+int main() {
+    counter cnt;
+    assert(cnt.get() == 0);
+    cnt.dec();
+    assert(cnt.get() == -1);
+    return 0;
+}
+