diff --git a/C++ Primer (5th Edition).pdf b/C++ Primer (5th Edition).pdf
new file mode 100644
index 0000000..38e943f
Binary files /dev/null and b/C++ Primer (5th Edition).pdf differ
diff --git a/ChangeLog b/ChangeLog
index 1d2d699..e51f8fa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2024-07-26  hwpplayer1  <hwpplayer1@debian>
+
+	* src/decleration.cpp: decleration example
+
+	* src/namespace_decleration.cpp: namespace / decleration example
+
+	* C++ Primer (5th Edition).pdf: 3.2. Library string Type page 125
+
 2024-07-03  hwpplayer1  <hwpplayer1@debian>
 
 	* README.md: Chapter 3. Strings, Vectors, and Arrays page 122
diff --git a/src/decleration.cpp b/src/decleration.cpp
new file mode 100644
index 0000000..98ef00c
--- /dev/null
+++ b/src/decleration.cpp
@@ -0,0 +1,13 @@
+#include <iostream>
+
+using std::cin;
+using std::cout; using std::endl;
+int main()
+{
+  cout << "Enter two numbers:" << endl;
+  int v1, v2;
+  cin >> v1 >> v2;
+  cout << "The sum of " << v1 << " and " << v2
+       << " is " << v1 + v2 << endl;
+  return 0;
+}
diff --git a/src/namespace_decleration.cpp b/src/namespace_decleration.cpp
new file mode 100644
index 0000000..98ef00c
--- /dev/null
+++ b/src/namespace_decleration.cpp
@@ -0,0 +1,13 @@
+#include <iostream>
+
+using std::cin;
+using std::cout; using std::endl;
+int main()
+{
+  cout << "Enter two numbers:" << endl;
+  int v1, v2;
+  cin >> v1 >> v2;
+  cout << "The sum of " << v1 << " and " << v2
+       << " is " << v1 + v2 << endl;
+  return 0;
+}