Introducing C++

Chapter 9. Strings and Formatting

You have used various types from the C++ standard library now, and you’ve learned about fundamental types like int and double. You have used characters, like '\n', and messages, like "Hello, world!", and even the std::string several times. I haven’t explained the differences between these types in detail yet, however. This chapter will go through the different string types and how to use them correctly.

You’ll learn about creating, manipulating, and formatting strings. I’ll show you how to make a string_view, a view that does not change a string. You will also see how to pass command-line arguments (which are C-style strings) to main so you can vary a program’s behavior.

You already have code to generate prices randomly and to read prices from a stream. In the hands-on part of the chapter, you’ll use these functions to make an improved version of your trading game, “Building a Trading Game”, against the various prices. This version will allow you to buy or sell stock, as well as displaying the prices in a neater way: I’ll show you how to print the prices to two decimal places, displaying them as “$100.00” rather than “100.”

C-Style String Literals and Characters

Make a new file called main_with_args.cpp. You’ll use it to experiment with the code in this section. I will provide some information on various string types first and then show you how to use them in a main function in the next section.

A single character uses single quotes (') and has ...