Implement n3668 - std::exchange

llvm-svn: 185863

1 files changed, 47 insertions, 0 deletions

diff --git a/libcxx/test/utilities/utility/exchange/exchange.pass.cpp b/libcxx/test/utilities/utility/exchange/exchange.pass.cpp
new file mode 100644
index 00000000000..b3603312ae4
--- /dev/null
+++ b/libcxx/test/utilities/utility/exchange/exchange.pass.cpp
@@ -0,0 +1,47 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// utilities
+
+// exchange
+
+#include <utility>
+#include <cassert>
+#include <string>
+
+int main()
+{
+#if _LIBCPP_STD_VER > 11
+	{
+	int v = 12;
+	assert ( std::exchange ( v, 23 ) == 12 );
+	assert ( v == 23 );
+	assert ( std::exchange ( v, 67.2 ) == 23 );
+	assert ( v = 67 );
+	}
+
+	{
+	bool b = false;
+	assert ( !std::exchange ( b, true ));
+	assert ( b );
+	}
+
+	{
+	const std::string s1 ( "Hi Mom!" );
+	const std::string s2 ( "Yo Dad!" );
+	std::string s3 = s1; // Mom
+	assert ( std::exchange ( s3, s2 ) == s1 );
+	assert ( s3 == s2 );
+	assert ( std::exchange ( s3, "Hi Mom!" ) == s2 );
+	assert ( s3 == s1 );
+	assert ( std::exchange ( s3, "" ) == s1 );
+	assert ( s3.size () == 0 );
+	}
+#endif
+}