finding "\n" in files

[Andreas Lassmann]

is there any way to find an endline in a file?
i.e:

xxxxxxxxxxxxxxxxx
x x x x x x x x x
xxxxxxxxxxxxxxxxx

is there some method in "ifstream"?
or can i check it with something like "if(fileInput == '\n')?

thanks in advance

 

[Dietmar Kuehl]

is there any way to find an endline in a file?

/**/ std::ifstream in("some file");
/**/ typedef std::istreambuf_iterator<char> iterator;
/**/ iterator it = std::find(iterator(beg), iterator(), '\n');
/**/ if (it != iterator())
/**/ std::cout << "found a newline\n";

 

[Victor Bazarov]

/**/ std::ifstream in("some file");
/**/ typedef std::istreambuf_iterator<char> iterator;
/**/ iterator it = std::find(iterator(beg), iterator(), '\n');

.. ^^^^^
What's "beg"? Did you mean

iterator it = std::find(iterator(in), iterator(), '\n');

?

/**/ if (it != iterator())
/**/ std::cout << "found a newline\n";

Thanks.

V

 

[Dietmar Kuehl]

. ^^^^^
What's "beg"? Did you mean

iterator it = std::find(iterator(in), iterator(), '\n');

?

Yes... I had a somewhat longer version which used a variable
named 'beg' first. Sorry, for the broken code.

 

[Mike Wahler]

is there any way to find an endline in a file?
i.e:

xxxxxxxxxxxxxxxxx
x x x x x x x x x
xxxxxxxxxxxxxxxxx

is there some method in "ifstream"?
or can i check it with something like "if(fileInput == '\n')?

thanks in advance

#include <ios>
#include <iostream>
#include <fstream>
#include <string>

int main()
{
std::ifstream input("filename");

if(input)
{
std::streamsize count(0);
std::string line;

while(std::getline(input, line) && !input.eof())
{
std::cout << "Last character read was a newline character\n";
++count;
}

if(!input.eof())
std::cerr << "Error occurred reading input\n";

std::cout << count << " newline characters found in input\n";
}
else
std::cerr << "Could not open input\n";

return 0;
}

 

[Thomas Matthews]

is there any way to find an endline in a file?
i.e:

xxxxxxxxxxxxxxxxx
x x x x x x x x x
xxxxxxxxxxxxxxxxx

is there some method in "ifstream"?
or can i check it with something like "if(fileInput == '\n')?

thanks in advance

Brute force:
ifstream my_file("my_file.txt")
char c;
while ((my_file >> c) && (c != '\n'))
{
; /* Illustrative null block */
}
/* At this point, the variable 'c' will
* contain a '\n'.
*/

There are better methods to read in text files.
I thought I'd show a brute force method.

--
Thomas Matthews

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