3.13. Functions with Results

You might have noticed by now that some of the functions we are using, like the math functions, yield results. Other functions, like new_line, perform an action but don’t return a value. That raises some questions:

• What happens if you call a function and you don’t do anything with the result (i.e. you don’t assign it to a variable or use it as part of a larger expression)?

• What happens if you use a function without a result as part of an expression, like new_line() + 7?

• Can we write functions that yield results, or are we stuck with things like new_line and print_twice?

The answer to the third question is “yes, you can write functions that return values,” and we’ll do it next chapter. I will leave it up to you to answer the other two questions by trying them out.

Note

Any time you have a question about what is legal or illegal in C++, a good way to find out is to ask the compiler. It will let you answer your question by throwing an error… or not!

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