array question

[foker]

I have an input file like test.txt which has 15 sentences in it on
different lines. Can I get 1 full line into 1 element of an array? Is
that possible? I try to do it and it will cut out at the first trailing
whitespace.

[mlimber]

foker wrote:

I have an input file like test.txt which has 15 sentences in it on
different lines. Can I get 1 full line into 1 element of an array? Is
that possible? I try to do it and it will cut out at the first trailing
whitespace.

Don't use arrays. They're evil
(http://www.parashift.com/c++-faq-lit...html#faq-34.1). Use a
std::vector of std::strings instead, and use std::getline to read. It
won't strip whitespace. See this post for an example:

http://groups.google.com/group/comp....9afd6f122340c8

Cheers! --M

[Default User]

foker wrote:

I have an input file like test.txt which has 15 sentences in it on
different lines. Can I get 1 full line into 1 element of an array? Is
that possible? I try to do it and it will cut out at the first
trailing whitespace.

How can we diagnose code that you keep hidden from us?

Brian
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[foker]

> How can we diagnose code that you keep hidden from us?

I have this
string get_sentence;
for(int i = 0; i < 15; i++)
{
fin >> get_sentence[i];
cout << get_sentence[i];
}

The problem with this is like I said above it only takes in the first
word into the first element of the array. I want to be able to put the
whole sentence into one element in the array. Not put 1 string in one
element or 1 char in one element.

[Amit Limaye]

u will do better with a vector
This is a string dunno wht happens when u index into a string.
with C -Style strings u get chars

-SIGTERM
amit

[Default User]

foker wrote:

How can we diagnose code that you keep hidden from us?
I have this
string get_sentence;
for(int i = 0; i < 15; i++)
{
fin >> get_sentence[i];
cout << get_sentence[i];
}

The problem with this is like I said above it only takes in the first
word into the first element of the array.

That's what << is designed to do. Your text should explain that.
I want to be able to put the
whole sentence into one element in the array.

What you need is getline().

As said elsewhere, you'd be better off with a std::vector of
std::string. Use the stand-alone version of getline():

std::string s;
std::vector v;

getline(fin, s); // fin is your file stream

v.push_back(s); // inserts a copy of the string
If you feel that you MUST use arrays, then the member version of
getline will work:

char s[256];

fin.getline(s,256);

Brian

[Default User]

Amit Limaye wrote:

u will do better with a vector
You will do better without shorthand like "u" and by quoting the
previous message. See the information in my .sig.
This is a string dunno wht happens when u index into a string.
with C -Style strings u get chars

I suggest a decent book on C++. This is pretty fundamental.
Brian
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[I V]

On Fri, 28 Apr 2006 13:21:32 -0700, foker wrote:

How can we diagnose code that you keep hidden from us?
I have this
string get_sentence;

This is a single string, not an array. Do you mean:

string get_sentence[15]

It's best to copy-and-paste (a short section of) your code into posts, so
that people can identify exactly what the problem is.
for(int i = 0; i < 15; i++)
Are you sure you'll always have exactly 15 sentences? It's better not to
hardcode this in - instead, use a vector which can resize to fit as many
sentences as you need.
{
fin >> get_sentence[i];
With the code you have here, that will input single character (and
produce undefined behavior, because you are trying to write to a
zero-length string). If you have an array of strings, it will (as you
report) input a string up to the first whitespace character. To read a
whole line into a string, use the getline function.
cout << get_sentence[i];
}

Try:

std::vector<std::string> sentences;
std::string one_sentence;

while( std::getline(fin, one_sentence) )
{
sentences.push_back(one_sentence);
std::cout << sentences.back() << std::endl;
}

[Jonathan Mcdougall]

Default User wrote:

foker wrote:

I want to be able to put the
whole sentence into one element in the array.
What you need is getline().

As said elsewhere, you'd be better off with a std::vector of
std::string. Use the stand-alone version of getline():

std::string s;
std::vector v;

This should be

std::vector<std::string> v;

I personally prefer to typedef container types since I often work with
iterators:

typedef std::vector<std::string> string_list;
string_list v;
getline(fin, s); // fin is your file stream
v.push_back(s); // inserts a copy of the string

Jonathan

[Default User]

Jonathan Mcdougall wrote:

Default User wrote:

foker wrote:

I want to be able to put the
whole sentence into one element in the array.

What you need is getline().

As said elsewhere, you'd be better off with a std::vector of
std::string. Use the stand-alone version of getline():

std::string s;
std::vector v;

This should be

std::vector<std::string> v;

Good pick, I was in a hurry.


Brian

[zw111_2001]

< C++ Primer 3rd Edition> Chapter 6, Section 7
Lippman has told you how to

[Rolf Magnus]

Jonathan Mcdougall wrote:

I personally prefer to typedef container types since I often work with
iterators:

typedef std::vector<std::string> string_list;

However, I wouldn't use the name 'string_list' for a vector of strings.
That's kind of misleading. When I read the name, my first expectation would
be that it's an std::list<std::string>.

[Default User]

zw********@163.com wrote:

< C++ Primer 3rd Edition> Chapter 6, Section 7
Lippman has told you how to

This sentence makes no sense. Context would probably help. See below.

Brian

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[Jonathan Mcdougall]

Rolf Magnus wrote:

Jonathan Mcdougall wrote:

I personally prefer to typedef container types since I often work with
iterators:

typedef std::vector<std::string> string_list;

However, I wouldn't use the name 'string_list' for a vector of strings.
That's kind of misleading. When I read the name, my first expectation would
be that it's an std::list<std::string>.

I use "list" in a generic way, as a "serie" of things. This allows me
to change the underlying representation of the "list" transparently (as
long as the operations are still valid, of course). Often the
implementation doesn't matter to the user (sometimes me), it is only
what I call an optimization. Matter of taste, perhaps.
Jonathan

[Richard Herring]

In message <11*********************@e56g2000cwe.googlegroups. com>,
Jonathan Mcdougall <jo***************@gmail.com> writes

Rolf Magnus wrote:

Jonathan Mcdougall wrote:

> I personally prefer to typedef container types since I often work with
> iterators:
>
> typedef std::vector<std::string> string_list;
However, I wouldn't use the name 'string_list' for a vector of strings.
That's kind of misleading. When I read the name, my first expectation would
be that it's an std::list<std::string>.

I use "list" in a generic way, as a "serie" of things.

So call it "series", or better "sequence", which is the real underlying
Concept.
This allows me
to change the underlying representation of the "list" transparently (as
long as the operations are still valid, of course). Often the
implementation doesn't matter to the user (sometimes me), it is only
what I call an optimization. Matter of taste, perhaps.

--
Richard Herring