Kyle Loudon - C++ Pocket Reference

With some minor exceptions, C++ was developed as an extension, or superset, of C. This means that well-written C programs generally will compile and run as C++ programs. (Most incompatibilities stem from the stricter type checking that C++ provides.) So, C++ programs tend to look syntactically similar to C and use much of C's original functionality.

This being said, don't let the similarities between C and C++ fool you into thinking that C++ is merely a trivial derivation of C. In fact, it is a rich language that extends C with some grand additions. These include support for object-oriented programming, generic programming using templates, namespaces, inline functions, operator and function overloading, better facilities for memory management, references, safer forms of casting, runtime type information, exception handling, and an extended standard library.

The function main is the designated start of a C++ program, which you as the developer must define. In its standard form, this function accepts zero or two arguments supplied by the operating system when the program starts, although many C++ implementations allow additional parameters. Its return type is int. For example:

argc is the number of arguments specified on the command line; argv is an array of null-terminated (C-style) strings containing the arguments in the order they appear. The name of the executable is stored in argv[0], and may or may not be prefixed by its path. The value of argv[argc] is 0.

The following shows the main function for a simple C++ program that prompts the user for actions to perform on an account:

The class for the account is defined in a later example. An initial deposit is made into the account using an amount specified on the command line when the program is started. The function atof (from the C++ Standard Library) is used to convert the command-line argument from a string to a double.