Counting the number of characters in a file

[mikebaily]

Hi

I want to write a program that opens a file and counts the number of characters in the file. If any one has a solution I would appreciate it.

Thanks in advance for your help.

[Philip Nicoletti]

#include <iostream>
#include <fstream>

int main()
{
  std::ifstream in("p.cpp",std::ios::binary);
  if (!in)
  {
     std::cout << "problem with file open" << std::endl;
     return 0;
  }


  in.seekg(0,std::ios::end);
  unsigned long length = in.tellg();

  std::cout << "number of characters (method 1) = " << length << std::endl;

  /////////

  in.seekg(0,std::ios::beg);

  int count = 0;
  char c;
  while(in.get(c))
      ++count;

  std::cout << "number of characters (method 2) = " << count << std::endl;


  return 0;
}

[mikebaily]

Thanks for your reply

I tried your program and it compiled but it wouldn't work - got the result of 0 characters when my .dat file contained around 20 characters.

Any ideas?

Thanks in advance for your help.

[Philip Nicoletti]

I tested on 4 different compilers, and it worked fine.

Are you using the standard headers <fstream> , or
the old non-standard headers <fstream.h>

Under Windows, I think that if you use the non-standard
headers, and the file does not exists, the error check
in the code doesn't work. (just to be sure: did you
change the name in the file open ? and is it in
the correct folder, etc.)

After my post, I editted it and added a second method.
Did you try that ?

[mikebaily]

Hi

I am using Windows XP and using Visual C++ 6

I have edited one bit of your code which is the file name. This is the code:

#include <iostream>
#include <fstream>

int main()
{
std::ifstream in("c:hello.dat",std::ios::binary);
if (!in)
{
std::cout << "problem with file open" << std::endl;
return 0;
}


in.seekg(0,std::ios::end);
unsigned long length = in.tellg();

std::cout << "number of characters (method 1) = " << length << std::endl;

/////////

in.seekg(0,std::ios::beg);

int count = 0;
char c;
while(in.get(c))
++count;

std::cout << "number of characters (method 2) = " << count << std::endl;


return 0;
}


I still get the problem that I get 0 returned when there are 20 characters in my dat file.

Any ideas?

Thanks in advance for your help

[Luis G]

that code should work.

Just for the sake of it, try this piece of C code

#include <stdio.h>


int main()
{
    FILE *myfile;
    unsigned long sizeofmyfile;
    myfile = fopen("myfile.dat","rb");
    if(myfile==NULL)
    {
        printf("could not open file\n");
        return -1;
    }

    fseek(myfile,0,SEEK_END);
    sizeofmyfile=ftell(myfile);
    printf("My file has a size of %ld bytes\n",sizeofmyfile);
    return 0;
} 

If 3 methods fail, then i'm pretty sure that you are doing something else wrong.