Update and Book added

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;
+}