more exercises

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diff --git a/iterator-test.cpp b/iterator-test.cpp
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+++ b/iterator-test.cpp
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+#include <iostream>
+#include <vector>
+#include "sales_data.hpp"
+#include "sales_item.hpp"
+
+/*
+ *
+ * Needed to test this program because i was
+ * confused about the condition in the for loop.
+ *
+ * Also some notes to get some things straight in my head
+ */
+
+using std::string;
+using std::cout;
+using std::cin;
+using std::cerr;
+using std::clog;
+using std::endl;
+using std::vector;
+int main () {
+
+	string s = "hello";
+	for (auto it = s.begin(); it != s.end() && !isspace(*it); ++it) {
+		*it = toupper(*it); // capitalize the current character
+	}
+	// BOTH need to be true for the loop to continue
+	cout << s << endl;
+
+	// print each line in text up to the first blank line
+	vector<string> text;
+	string s1 = "hello!";
+	string s2 = "hello vro";
+	string s3 = "ffffff";
+	string s4;
+	string s5 = "yo";
+	text.push_back(s1);
+	text.push_back(s2);
+	text.push_back(s3);
+	text.push_back(s4);
+	text.push_back(s5);
+	for (auto it = text.cbegin() ; // Get the beginning element
+		 it != text.cend() && !it->empty() ; ++it) { /* loop stops when we hit the end or if theres an empty string.
+														we do this by accessing the method empty() through the arrow operator
+													  */
+		cout << *it << endl;
+		cout << it->at(0) << endl; // To access the individual characters in the strings in the vector we use at() method
+		cout << (*it)[0] << endl; // We can also do it this way.
+	}
+
+	/*
+	  Example for myself:
+	  we try to access method in dereferenced s1.empty()
+	  but because we are dereferencing and accessing method at the same time we have a special operator
+	  -> dereference while also accessing a member
+	 */
+	
+	/*
+	  'it' is a const iterator which is (kind of) a pointer? Kinda?
+	  It points towards the first element (cbegin()). Which is a string.
+	  But we want to use methods from the string class. So we have to use the
+	  arrow operator to access that method.
+
+	  I've used C before so i am a bit familiar with using the arrow operator
+	  in structs. Though i will say that this does feel a bit different because
+	  classes in this language dont just have data types in the structs but also
+	  methods so yeah i guess it makes sense that we use the -> arrow operator
+	  to access those methods. If we were to access a method but directly on a string
+	  (not through a pointer / iterator) then yeah we would be using the . operator.
+
+	  So i guess this all makes sense. I just had to write this text to get everything
+	  clear in my head
+	 */
+	return 0;
+}