C++ Language Tutorial — Basics of C++: Structure of a Program
Initially, I looked at C++ Language Tutorial by Juan SouliƩ, but I found Thinking in C++ by Bruce Eckel recommended on the KDE development page, so I am going to read both.
At first glance, Eckel’s book looks like a really heavy read. If I may say so, it’s very… hard-core? Perhaps bleak? Okay, I may be biased toward pretty, colorful code blocks used in the C++ Language *Tutorial*, but really—Eckel’s first chapter is a slightly ominous, philosophical “Introduction to Objects.” The chapters are much more detailed than SouliĆ©’s tutorial (after all, it’s just that, a tutorial).
Hopefully, I’ll be able to pluck up some courage to read that chapter once I’ve learned a reasonable amount of syntax and structure. It seems like a great book, but it looks way too scary right now.
So getting started with the tutorial:
A basic C++ program as a model, copied from the site:
// my first program in C++ #include using namespace std; int main () { cout << "Hello World!"; return 0; }
All text after two slash signs (//
) are comments. Block comments can be inserted between /*
and */
.
Lines beginning with a hash sign (#
) are directives for the preprocessor. In this example, #include
tells the preprocessor to include the iostream file, which is the basic input-output library in C++ (which defines cout
).
“All the elements of the standard C++ library are declared within what is called a namespace
… with the name std
.” We call it with using namespace std
, and it is frequently used in C++ programs that use the standard library.
int main ()
is the beginning of the definition of the main
function, which is where all C++ programs start their execution. Other functions may be defined elsewhere and anywhere, but the main
function will be executed first (thus is essential to every C++ program). The parentheses can optionally enclose a list of parameters. The body of the function is enclosed in a pair of braces.
A statement is an expression that can produce an effect. cout << "Hello World!";
outputs the string of characters Hello World!
into the standard output (e.g., the screen). All expression statements are terminated by a semicolon.
The return
statement in this example is followed by a return code of 0
, which generally indicates a successful execution of the program. C++ console programs are usually ended in this way.
With the exception of lines of preprocessor directives (they are not statements), whitespace is insignificant. Semicolons are important.