Read line after line but from the eof.

[Ground21]

Hello.
How could I read the whole text file line after line from the end of
file? (I want to ~copy~ file)

I want to copy file in this way:

file 1:

a
b
c
file 2:

c
b
a
--
Ground21_______ _____\\
ground21@poczta KROPKAfm

[Rolf Magnus]

Ground21 wrote:

red floyd napisał(a):

>1. What is "lines"?

int lines=0;
fseek(fileh,0L, SEEK_SET);
while(feof(file h)==0) if(fgetc(fileh) =='\n') linies++;

lines - number of lines in my text file.

>2. What happens if there are more than 10 lines in a file?

I read in wikibooks, that value of size will automaticlly increase if
necessary...

Yes, if you use the push_back member function.

>3. What happens if a line is bigger than 256?

I know, that it can be done better using something like strlen to check
line lenght, but for me, 256 is OK.

It would be better as well as easier to use std::string instead of raw char
arrays and pointers.

>4. Why are you using arrays and C-style I/O?
5. What is <vector.h>? The C++ header is <vector>

in c++ builder 6 it works the same for <vectorand <vector.h>...

Well, then you better stick to the standard header <vector>, otherwise your
program will be non-portable.

>6. Every entry in your vector is identical, since you're storing the
same address over and over.

I though, that I take first line to tab[0], second line to tab[1]...

You could try something based on this (untested):

#include <istream>
#include <ostream>
#include <string>
#include <vector>

void reverse_copy_fi le(std::istream & infile, std::ostream& outfile)
{
typedef std::vector<std ::string vec_type;
vec_type text;

std::string line;
while (std::getline(i nfile, line))
text.push_back( line);

vec_type::const _reverse_iterat or it = text.rbegin(), end = text.rend();
for (; it != end; ++it)
outfile << line << '\n';
}

[Ground21]

r wrote:

// reading a file line by line
std::ifstream ifs ("tmp.txt");
std::string line;
std::vector<std ::stringlines;
while (getline (ifs, line)) {
lines.push_back (line);
}

Is this already in the C++ FAQ?

[C++ Error] zapis.cpp(136): E2285 Could not find a match for
'getline<_CharT ,_Traits,_Alloc >(FILE *,string)'

--
Ground21_______ _____\\
ground21@poczta KROPKAfm

[red floyd]

Ground21 wrote:

r wrote:

>// reading a file line by line
std::ifstrea m ifs ("tmp.txt");
std::string line;
std::vector<st d::stringlines;
while (getline (ifs, line)) {
lines.push_back (line);
}

Is this already in the C++ FAQ?

[C++ Error] zapis.cpp(136): E2285 Could not find a match for
'getline<_CharT ,_Traits,_Alloc >(FILE *,string)'

That's because you didn't copy the whole example. He used an ifstream
for input, not a FILE*.

Use C++ style I/O if you're writing C++.

[BobR]

Ground21 wrote in message ...

>Rolf Magnus napisał(a):

>Yup. What you should do is read the file line by line and put each line as

a

>separate string into a vector. So later you have a vector of lines. Then
you can iterate through that vector backwards and write the strings out
again.

can You tell me what's wrong with this code?:
(I want to save lines from file 'file' to vectors, and then, write them
into "tmp.txt"). I got wrong output "tmp.log".. . I think that is problem
with char*...

// >#include <vector.h>
#include <vector// C++

>vector <char*tab(10) ;
tmp=fopen("tmp. txt","w");
fseek(file, 0L, SEEK_SET);
for(int i=0; i<lines; i++){
fgets(tab[i],256,file);
}
for(int i=lines; i>0; i--){
fputs(tab[i],tmp);
}

#include <vector// C++
#include <string>
#include <fstream>
#include <algorithm>

int main(){
std::ifstream copin( "ZZtest.txt " );
if( not copin.is_open() ){ throw "a fit";}

std::vector<std ::stringTmpFile ;
for( std::string line; std::getline( copin, line ); ){
TmpFile.push_ba ck(line);
}
// copin.close();
std::reverse( TmpFile.begin() , TmpFile.end() ); // reverse it
std::ofstream out( "ZZtestR.tx t" );
for( size_t i(0); i < TmpFile.size(); ++i ){
std::reverse( TmpFile.at(i).b egin(), TmpFile.at(i).e nd());
out<< TmpFile.at( i ) <<std::endl;
}
// out.close();
} // main()
// ----------
// - contents "ZZtest.txt " -
Record 0
Record 1
Record 2
Record 3
Record 4
Record 5
Record 6

// - contents "ZZtestR.tx t" -
6 droceR
5 droceR
4 droceR
3 droceR
2 droceR
1 droceR
0 droceR

--
Bob R
POVrookie

[Tobias Gneist]

Ground21 wrote:

Hello.
How could I read the whole text file line after line from the end of
file? (I want to ~copy~ file)

I want to copy file in this way:

file 1:

a
b
c
file 2:

c
b
a

I think the most simple solution would use a stack an C++ I/O.

#include <iostream>
#include <fstream>
#include <stack>
#include <string>

using namespace std;

int main()
{
ifstream in("in.txt");
ofstream out("out.txt");
stack<stringss;

string s;
in >s;
while (!in.eof()) {
ss.push(s);
in >s;
}
while (!ss.empty()) {
out << ss.top() << endl;
ss.pop();
}
return 0;
}

[Rolf Magnus]

Tobias Gneist wrote:

Ground21 wrote:

>Hello.
How could I read the whole text file line after line from the end of
file? (I want to ~copy~ file)

I want to copy file in this way:

file 1:

a
b
c
file 2:

c
b
a

I think the most simple solution would use a stack an C++ I/O.

Hmm, right. A stack is actually a better choice than a vector.

#include <iostream>
#include <fstream>
#include <stack>
#include <string>

using namespace std;

int main()
{
ifstream in("in.txt");
ofstream out("out.txt");
stack<stringss;

string s;
in >s;
while (!in.eof()) {
ss.push(s);
in >s;
}

Simpler and more correct than those last 5 lines would be:

while (in >s)
ss.push(s);

while (!ss.empty()) {
out << ss.top() << endl;

No need to flush the stream after each line, so '\n' instead of endl is
sufficient.

ss.pop();
}
return 0;
}

[gongzibi]

I think the most simple solution would use a stack an C++ I/O.

>
#include <iostream>
#include <fstream>
#include <stack>
#include <string>

using namespace std;

int main()
{
ifstream in("in.txt");
ofstream out("out.txt");
stack<stringss;

string s;
in >s;
while (!in.eof()) {
ss.push(s);
in >s;
}

If input likes:

test
122 345 345

output would be:

345
345
122
test

How about this

while (std::getline(i n,s)) {
ss.push(s);
}

output would be:

122 345 345
test

while (!ss.empty()) {
out << ss.top() << endl;
ss.pop();
}
return 0;
}

[Ground21]

gongzibi napisał(a):

How about this

while (std::getline(i n,s)) {
ss.push(s);
}

output would be:

122 345 345
test

ifstream in("log.txt");
ofstream out("out.txt");
stack<stringss;

string s;
in >s;

while (std::getline(i n,s)) {
ss.push(s);
}
while (!ss.empty()) {
out << ss.top() << endl;
ss.pop(); }

this code works OK, but...

my log.txt file:

d/t: 2006-12-23/18:52:47 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:49 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:50 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:52 D:\c++\sem1\Pro ject1.exe

and output file:

d/t: 2006-12-23/18:52:52 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:50 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:49 D:\c++\sem1\Pro ject1.exe
2006-12-23/18:52:47 D:\c++\sem1\Pro ject1.exe

where is my "d/t: " ?
--
Ground21_______ _____\\
ground21@poczta KROPKAfm

[BobR]

Ground21 wrote in message ...

>
ifstream in("log.txt");
ofstream out("out.txt");
stack<stringss;

string s;
in >s;

while (std::getline(i n,s)) {
ss.push(s);
}
while (!ss.empty()) {
out << ss.top() << endl;
ss.pop(); }

this code works OK, but...

my log.txt file:

d/t: 2006-12-23/18:52:47 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:49 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:50 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:52 D:\c++\sem1\Pro ject1.exe

and output file:

d/t: 2006-12-23/18:52:52 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:50 D:\c++\sem1\Pro ject1.exe
d/t: 2006-12-23/18:52:49 D:\c++\sem1\Pro ject1.exe
2006-12-23/18:52:47 D:\c++\sem1\Pro ject1.exe

where is my "d/t: " ?

string s;
in >s; // it's in this string you didn't save.
// delete that line.

while (std::getline(i n,s)) { ss.push(s); }

--
Bob R
POVrookie

[Ground21]

BobR napisał(a):

>where is my "d/t: " ?

string s;
in >s; // it's in this string you didn't save.
// delete that line.

while (std::getline(i n,s)) { ss.push(s); }

works great!
thanks a lot!

--
Ground21_______ _____\\
ground21@poczta KROPKAfm