Add .gitignore and IntelliJ IDEA project configuration files and projects for cpp intro, pointers and classes

cpp/classes/ClassA.cpp

@@ -0,0 +1,12 @@
+#include "ClassA.h"
+
+#include <iostream>
+
+void ClassA::Print()
+{
+    std::cout << "ClassA" << std::endl;
+}
+
+int ClassA::CompareTo(IComparable *other) {
+    return 0;
+}