examples from C++ Primer but with own mind/consciousness

src/calculate.cpp

@@ -0,0 +1,12 @@
+#include <iostream>
+
+int main()
+{
+  std::cout << "enter two numbers:" << std::endl;
+  int value1 = 0, value2 = 0;
+  std::cin >> value1 >> value2;
+  std::cout << "The sum of " << value1 << " and " << value2
+	    << " is " << value1 + value2 << std::endl;
+
+  return 0;
+}