diff --git a/interpreter.cpp b/interpreter.cpp
index 5599ccb..632f492 100644
--- a/interpreter.cpp
+++ b/interpreter.cpp
@@ -9,7 +9,7 @@
 #include "interpreter.hpp"
 #include <cctype>
 #include <algorithm>
-#include <iostream>
+#include <sstream>
 
 int to_int(const std::string& val) {
     std::istringstream iss {val};
diff --git a/interpreter.hpp b/interpreter.hpp
index 3415dfb..1601962 100644
--- a/interpreter.hpp
+++ b/interpreter.hpp
@@ -14,7 +14,6 @@
 #include <vector>
 #include <map>
 #include <stdexcept>
-#include <sstream>
 
 class syntax_error : public std::runtime_error {
     public:
@@ -34,11 +33,11 @@ class interpreter {
     private:
         std::vector<std::string> _prog; // program lines without label defs or comments
         std::vector<std::string> _values; // value stack
-        std::map<std::string, size_t> _labels; // label name => prog line index
-        std::map<std::string, std::string> _vars; // var name => string value
         std::vector<size_t> _calls; // call stack
+        std::map<std::string, size_t> _labels; // label name => prog line index
+        std::map<std::string, std::string> _vars; // variable name => string value
         size_t _pc {0}; // current program counter (index into _prog)
-        std::vector<size_t> _pc_offsets; // removed line indices for prog index => source line
+        std::vector<size_t> _pc_offsets; // removed line indices for: prog index => source line
 
         void reset();
         void exec_instruction(const std::string& code, bool& done);