programming-for-dummies

280
Adding Comments to Source Code
A block comment lets you identify the beginning and end of a comment. So if
you wanted to write a comment on two separate lines in C++, you’d have to
type the // symbols in front of each line, such as
// Calculates the hypotenuse of a triangle (C)
// using the Pythagoras theorem: C 2 = A 2 + B 2
If you created this as a block comment, you could use the /* and */
symbols to mark the start and end of a comment like this:
/* Calculates the hypotenuse of a triangle (C)
using the Pythagoras theorem: C 2 = A 2 + B 2
*/
No matter how many comments you add, you only need to use the /* and
*/ comment symbols once like this:
/* Calculates the hypotenuse of a triangle (C)
using the Pythagoras theorem: C 2 = A 2 + B 2 .
The length of the hypotenuse is then used to
move a cartoon figure on the screen.
*/
Block comments just make it easier to add multiple lines of comments.
Programmers often use both line and block comments in a single program
like this:
/* Calculates the hypotenuse of a triangle (C)
using the Pythagoras theorem: C 2 = A 2 + B 2 .
The length of the hypotenuse is then used to
move a cartoon figure on the screen.
*/
c = sqrt(a * a + b * b) // Pythagoras theorem
The comment symbol in one language may have a completely different
meaning in another language, so make sure you don’t mix them up.
✦ In the curly bracket languages (such as C++ and Java), the curly brackets
are used to define a block of commands like this:
int main()
{
cout