2 files changed, 5 insertions, 2 deletions
diff --git a/src/simpl/base.cpp b/src/simpl/base.cpp
index 4e34dfd..e126433 100644
--- a/src/simpl/base.cpp
+++ b/src/simpl/base.cpp
@@ -40,7 +40,7 @@ Peak::~Peak()
 }
 
 // Returns true iff this peak is unmatched in the given direction, and has positive amplitude
-bool Peak::is_free(const char* direction)
+bool Peak::is_free(string direction)
 {
     if(amplitude <= 0.0)
     {
diff --git a/src/simpl/base.h b/src/simpl/base.h
index 88ff0e9..59a969e 100644
--- a/src/simpl/base.h
+++ b/src/simpl/base.h
@@ -20,9 +20,12 @@
  */
 
 #include <vector>
+#include <string>
 
 #include "exceptions.h"
 
+using namespace std;
+
 namespace Simpl 
 {
 
@@ -48,7 +51,7 @@ public:
     {
         return previous_peak == NULL;
     };
-    bool is_free(const char* direction="forwards");
+    bool is_free(string direction = string("forwards"));
 };
 
 typedef std::vector<Peak> Peaks;