Strings/Nesting Comments
Author
Two quick (I assume) questions that I have come across.
1. Is there any benefit to nesting comments?
As in:
/* //Comment
//Comment
*/
2. What is the most common usage of strings?
To be honest I can't think of any situation in which i'd want to nest comments, but it also doesn't make sense.
Anything after the comment marks is ignored by the compiler, comments are only for yourself to make your code easier to read. Therefore, unless you think it improves the readability of your code, you can use the style you showed. ( I think it doesn't improve readability though :P ).
Some comment styles I often use:
As you can see "nesting" would only make it less readable.
As to your second question, as soon as you are starting to work with text in your applications the string class is going to be of use. Technically you could handle text just with character arrays but std::string is not only so much easier, it's also much safer than using character arrays. Therefore, I recommend you use std::string as often as possible when you need to store text ;)
Anything after the comment marks is ignored by the compiler, comments are only for yourself to make your code easier to read. Therefore, unless you think it improves the readability of your code, you can use the style you showed. ( I think it doesn't improve readability though :P ).
Some comment styles I often use:
// Just a quick comment for above a variable or something// -------------------------------------// Name: Function name here// Info: Function description here// Return value: return value here.// -------------------------------------/* short comment between code *//* * This style could be used for commenting the start of a file. * Filename: * Author: * Date: * *///// Or this, I like it better than those asterisks...//As you can see "nesting" would only make it less readable.
As to your second question, as soon as you are starting to work with text in your applications the string class is going to be of use. Technically you could handle text just with character arrays but std::string is not only so much easier, it's also much safer than using character arrays. Therefore, I recommend you use std::string as often as possible when you need to store text ;)
You can use /* */ to temporarily remove code from being compiled, for testing usually. In c++ you can use
#if 0
// stuff you want commented
#endif
the #if way is better because nested /**/ comments dont work, the compiler will only catch the indicated code:
/*
int x;
/*
int y;
*/
int z; // oh no, this is included
*/ //<--- compiler will complain about this one, its not syntactically correct
As its quite common to have /* */ comments littered throughout code, it can make commenting out large blocks a pain.
Its hard to think of many useful programs where strings aren't used...
#if 0
// stuff you want commented
#endif
the #if way is better because nested /**/ comments dont work, the compiler will only catch the indicated code:
/*
int x;
/*
int y;
*/
int z; // oh no, this is included
*/ //<--- compiler will complain about this one, its not syntactically correct
As its quite common to have /* */ comments littered throughout code, it can make commenting out large blocks a pain.
Its hard to think of many useful programs where strings aren't used...
Author
Alright, I though as much as far as the comments went, but I was reading a site in which it said you could. I guess you "can" do anything. :P
But in terms of strings, (I don't really understand what a character array is), you are saying that if I want to say Hi once, that I should just use COUT, but if I want to say it a hundred times, use strings?
But in terms of strings, (I don't really understand what a character array is), you are saying that if I want to say Hi once, that I should just use COUT, but if I want to say it a hundred times, use strings?
Quote:Original post by Gallivan
1. Is there any benefit to nesting comments?
As in:
/* //Comment
//Comment
*/
Usually when you see this it is because someone "commented out" a piece of code that contained comments itself. This is a common way to remove a chunk of code while debugging.
Quote:Original post by Gallivan
But in terms of strings, (I don't really understand what a character array is), you are saying that if I want to say Hi once, that I should just use COUT, but if I want to say it a hundred times, use strings?
No, a string (or a character array) is simply an array of numbers where each number is the ASCII (or UNICODE) code of a character. C-style strings are null-terminated, so they contain an additional number zero at the end.
cout << "This is a string" << endl;
If you wanted to print that out a hundred times you have to use a for loop:
for(int i=0; i<100; i++)
cout << "This is a string" << endl;
Author
Ok thanks to everyone above for their EXTREMELY speedy responses. But I am stilling having a bit of confusion about where and when to use strings? From what I have read, which I am sure has not covered even the most basic uses of strings, they are only used in text?
Here is an example from the site I am reading through:
// my first string
#include <iostream>
#include <string>
using namespace std;
int main ()
{
string mystring;
mystring = "This is the initial string content";
cout << mystring << endl;
mystring = "This is a different string content";
cout << mystring << endl;
return 0;
}
And on a different note, how do I incorporate that into a small white box?
Here is an example from the site I am reading through:
// my first string
#include <iostream>
#include <string>
using namespace std;
int main ()
{
string mystring;
mystring = "This is the initial string content";
cout << mystring << endl;
mystring = "This is a different string content";
cout << mystring << endl;
return 0;
}
And on a different note, how do I incorporate that into a small white box?
and <code> don't seem to work.
Strings by definition are text, so that's what they are used for: displaying text on the screen or capturing text from the keyboard. In C++ whenever you see an std::string variable, you can bet that the variable contains some sort of text.
EDIT: I guess what you are really asking is why do we need to use std::string when we can just use literal strings directly? For instance, these two pieces of code do exactly the same thing:
cout << "Hi" << end; //print out the literal string
string hi = "Hi"; //save the literal string so we can use it later
cout << hi << endl; //print out the std::string object
The reason why you would want to use an std::string object is in case you don't know in advance what kind of text should be in the string. For example:
string message = getMessage(); //this function returns the text that needs to be printed out (perhaps the text comes from an instant messaging application)
cout << message << endl; //this prints out whatever was returned from the above function
[Edited by - deathkrush on September 20, 2006 6:37:36 PM]
EDIT: I guess what you are really asking is why do we need to use std::string when we can just use literal strings directly? For instance, these two pieces of code do exactly the same thing:
cout << "Hi" << end; //print out the literal string
string hi = "Hi"; //save the literal string so we can use it later
cout << hi << endl; //print out the std::string object
The reason why you would want to use an std::string object is in case you don't know in advance what kind of text should be in the string. For example:
string message = getMessage(); //this function returns the text that needs to be printed out (perhaps the text comes from an instant messaging application)
cout << message << endl; //this prints out whatever was returned from the above function
[Edited by - deathkrush on September 20, 2006 6:37:36 PM]
Quote:Original post by Gallivan
But I am stilling having a bit of confusion about where and when to use strings?
strings can be used in forms where a person's name, address, or phone number are required; places where a numeric variable could not hold their possible values. a good way to figure out when to use a string rather than numeric data types is if your program isn't going to need to arithmetically modify or test the data. data such as phone numbers or ssn, should not be stored in numeric data types, even though they have mostly, or entirely all numbers.
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