Comments

As noted above, comments do not affect the operation of the program; however, they provide an important tool to document directly within the source code what the program does and how it operates.

C++ supports two ways of commenting code:

1 2

// line comment /* block comment */

The first of them, known as line comment, discards everything from where the pair of slash signs (//) are found up to the end of that same line. The second one, known as block comment, discards everything between the /* characters and the first appearance of the */ characters, with the possibility of including multiple lines.

Let's add comments to our second program:

/* my second program in C++
with more comments */

#include

int main ()
{
std::cout << "Hello World! "; // prints Hello World!
std::cout << "I'm a C++ program"; // prints I'm a C++ program
}


Output

Hello World! I'm a C++ program

If comments are included within the source code of a program without using the comment characters combinations //, /* or */, the compiler takes them as if they were C++ expressions, most likely causing the compilation to fail with one, or several, error messages.

... Qweit ...