 <p>String literals are simply zero terminated array of chars in C++. There is no operator that allows you to add 2 arrays of chars in C++. </p> <p>There is however a char array and std::string + operator.</p> <p>Change to: </p> <pre><code>const std::string message = std::string("Hello") +", world" + exclam; </code></pre> <p>In some languages like Python string literals are equivalent to variables of type strings. C++ is not such a language.</p>