C++

8.4    The Expression Statement

You can also use any expression as a statement. Although it makes little sense to use 3+4; as a statement, for example, assignments are expressions and are used as statements very often.

Assuming you have previously declared int upTo;, the following listing gives examples of expressions used as statements.

upTo = 99;                    // an assignment is an expressionupTo = upTo * 2 + 1;          // combining an assignment with a calculationcalculatePrimesUpTo(upTo);    // a function call is an expressionstd::cout << "Friedrich III"; // the output operator  

Listing 8.9     These are all expressions used as statements.

As I mentioned earlier, every expression has a value and a type. If an expression is used as a statement, the type disappears ...