Add examples

Author: hristo-vrigazov

cpp/examples/and_keyword.cpp

@@ -0,0 +1,12 @@
+#include <iostream.h>
+
+using namespace std;
+
+int main()
+{
+    if (true and true) {
+        cout << "Hello World!";
+    }
+    return 0;
+}
+

cpp/examples/not_keyword.cpp

@@ -0,0 +1,12 @@
+#include <iostream.h>
+
+using namespace std;
+
+int main()
+{
+    if (not false) {
+        cout << "Hello World!";
+    }
+    return 0;
+}
+

cpp/examples/or_keyword.cpp

@@ -0,0 +1,12 @@
+#include <iostream.h>
+
+using namespace std;
+
+int main()
+{
+    if (false or true) {
+        cout << "Hello World!";
+    }
+    return 0;
+}
+