1 files changed, 35 insertions, 0 deletions
diff --git a/4p20.cpp b/4p20.cpp
new file mode 100644
index 0000000..edc38ce
--- /dev/null
+++ b/4p20.cpp
@@ -0,0 +1,35 @@
+#include <iostream>
+#include <iterator>
+#include <vector>
+
+/*
+ *
+ * 4.20
+ *
+ *
+ */
+
+int main () {
+
+	std::string s1 = "Wow!";
+	std::string s2 = "C++ is very cool, i like it!";
+	std::string s3 = "I also really like C!";
+	std::vector<std::string> vs;
+	vs.push_back(s1);
+	vs.push_back(s2);
+	vs.push_back(s3);
+	std::vector<std::string>::iterator iter = vs.begin();
+	std::cout << *iter++ << std::endl;
+	std::cout << iter->empty() << std::endl;
+	std::cout << iter++->empty() << std::endl;
+	/*
+	  (a) *iter++; // valid
+	  (b) (*iter)++; // not valid? we dereference and try to increment a string which does not work
+	  (c) *iter.empty() // not valid, we try to call .empty() member function on an iterator, which does not exist
+	  (d) iter->empty(); // valid
+	  (e) ++*iter; // not valid, we are dereferencing and then trying to increment a string. I am a bit confused because i thought precedence of the ++ operator would make it increment first and then dereference it but it does not seem so...
+	  (f) iter++->empty(); // valid
+	 */
+	
+	return 0;
+}