problem using strlen

[ricky]

What is worng with my code.
I can reads all the lines all right but it doesn't return me the length
of lines.
It returns 0 for each line

#include <fstream>
#include <istream>
#include <iostream>
#include <ostream>
#include <string>

int main()
{
fstream in("example.txt ");
static string line;
int len = line.length();
while(getline(i n,line))
{
cout<< line <<'\n';
cout<<len<<endl ;
}
return 0;
}

[Stefan Näwe]

Re: problem using strlen

ricky schrieb:

What is worng with my code.
I can reads all the lines all right but it doesn't return me the length
of lines.
It returns 0 for each line
>
#include <fstream>
#include <istream>
#include <iostream>
#include <ostream>
#include <string>
>
int main()
{
fstream in("example.txt ");
static string line;
int len = line.length();

How often does this ^^^^^ get executed ?

while(getline(i n,line))
{
cout<< line <<'\n';
cout<<len<<endl ;
}
return 0;
}
>

/S
--
Stefan Naewe
naewe.s_AT_atla s_DOT_de

[Siam]

Re: problem using strlen

You're creating an empty string (line)....and setting its length to the
len variable. As you then put strings into your line, the len variable
is never recalculated... it remains at what it started at i.e. 0. In
other words, the len variable doesn't dynamically update itself every
time you're line changes...you need to explicitly recalculate the
string length each time...ie.

while(getline(i n,line))
{
len = line.length();
cout<< line <<'\n';
cout<<len<<endl ;
}

ricky wrote:

What is worng with my code.
I can reads all the lines all right but it doesn't return me the length
of lines.
It returns 0 for each line
>
#include <fstream>
#include <istream>
#include <iostream>
#include <ostream>
#include <string>
>
int main()
{
fstream in("example.txt ");
static string line;
int len = line.length();
while(getline(i n,line))
{
cout<< line <<'\n';
cout<<len<<endl ;
}
return 0;
}

[Eric Pruneau]

Re: problem using strlen


"ricky" <ricky_nme@yaho o.co.ina écrit dans le message de news:
1154438359.9764 88.176400@i42g2 00...legr oups.com...

What is worng with my code.
I can reads all the lines all right but it doesn't return me the length
of lines.
It returns 0 for each line
>
#include <fstream>
#include <istream>
#include <iostream>
#include <ostream>
#include <string>
>
int main()
{
fstream in("example.txt ");
static string line;
int len = line.length();

this should gives you 0

while(getline(i n,line))

extract a line from the text file.. ok

{
cout<< line <<'\n';

print the line

cout<<len<<endl ;

print len which is still 0 because you get the lenght before getting the
string

}
return 0;

oupss forget to close the file....

}
>

[ricky]

Re: problem using strlen

Great!! that worked
thanks Siam...
Siam wrote:

You're creating an empty string (line)....and setting its length to the
len variable. As you then put strings into your line, the len variable
is never recalculated... it remains at what it started at i.e. 0. In
other words, the len variable doesn't dynamically update itself every
time you're line changes...you need to explicitly recalculate the
string length each time...ie.
>
while(getline(i n,line))
{
len = line.length();
cout<< line <<'\n';
cout<<len<<endl ;
}
>
ricky wrote:

What is worng with my code.
I can reads all the lines all right but it doesn't return me the length
of lines.
It returns 0 for each line

#include <fstream>
#include <istream>
#include <iostream>
#include <ostream>
#include <string>

int main()
{
fstream in("example.txt ");
static string line;
int len = line.length();
while(getline(i n,line))
{
cout<< line <<'\n';
cout<<len<<endl ;
}
return 0;
}

[ricky]

Re: problem using strlen

Yeah it is working now.
thanks to all of u.
Eric Pruneau wrote:

"ricky" <ricky_nme@yaho o.co.ina écrit dans le message de news:
1154438359.9764 88.176400@i42g2 00...legr oups.com...

What is worng with my code.
I can reads all the lines all right but it doesn't return me the length
of lines.
It returns 0 for each line

#include <fstream>
#include <istream>
#include <iostream>
#include <ostream>
#include <string>

int main()
{
fstream in("example.txt ");
static string line;
int len = line.length();

>
this should gives you 0
>

while(getline(i n,line))

>
extract a line from the text file.. ok

{
cout<< line <<'\n';

print the line

cout<<len<<endl ;

print len which is still 0 because you get the lenght before getting the
string

}
return 0;

oupss forget to close the file....

}

[Default User]

Re: problem using strlen

Siam wrote:

You're creating an empty string (line)

Please see my .sig below.



Brian
--
Please don't top-post. Your replies belong following or interspersed
with properly trimmed quotes. See the majority of other posts in the
newsgroup, or the group FAQ list:
<http://www.parashift.c om/c++-faq-lite/how-to-post.htm>

[Default User]

Re: problem using strlen

ricky wrote:

Great!! that worked

Please see my .sig below.



Brian
--
Please don't top-post. Your replies belong following or interspersed
with properly trimmed quotes. See the majority of other posts in the
newsgroup, or the group FAQ list:
<http://www.parashift.c om/c++-faq-lite/how-to-post.htm>

[Marcus Kwok]

Re: problem using strlen

Eric Pruneau <epruneau@infin ition.comwrote:

>
"ricky" <ricky_nme@yaho o.co.ina ?crit dans le message de news:
1154438359.9764 88.176400@i42g2 00...legr oups.com...

>What is worng with my code.
>I can reads all the lines all right but it doesn't return me the length
>of lines.
>It returns 0 for each line
>>
>#include <fstream>
>#include <istream>
>#include <iostream>
>#include <ostream>
>#include <string>
>>
>int main()
>{
>fstream in("example.txt ");

[code elided]

oupss forget to close the file....
>

>}

It is not necessary, since fstream's destructor will take care of that
when "in" goes out of scope. That is the point of RAII.

--
Marcus Kwok
Replace 'invalid' with 'net' to reply