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Convert Data....???

Posted on 2001-07-06
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Last Modified: 2013-11-20
#include <fstream>
//Get data from text file (test.txt);
//Can I use CString to replace text file?
//And how?

ifstream m("test.txt");
CalcLexer lexer(m);

How to convert  data CString ->ifstream
(but I don't want to save CString ->textfile).
Thanks
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Question by:pbtdanh
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5 Comments
 
LVL 12

Accepted Solution

by:
migel earned 100 total points
ID: 6259020
Hi!
to read data from file:
CString strBuffer;
// get size of the file
m.seekp(0, ios::end);
streampos lpos = m.tellp();
m.seekp(0, ios::beg);
// lpos now is the size of the stream
char* pszBuff = strBuffer.GetBufferSetLength(lpos + 1);
if (pszBuffer)
{
// read it in the buffer
ofs.read(pszBuffer, lpos);
strBuffer.ReleaseBuffer();
}

But if you already have data not in file
you can use stringstream intead ifstream  but iif your function uses ifstreamas parameter not basic_ios or basic_istream then you need rewrite it to use basic stream classes instead particular derived.
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LVL 3

Expert Comment

by:pamboo
ID: 6259023
>>CalcLexer lexer(m);

will  u please explain ur problem elaborately

I think u want to read a file and store datas in a CString

0
 
LVL 30

Assisted Solution

by:Axter
Axter earned 100 total points
ID: 6262544
pbtdanh,

You're using the wrong class to store/write data.
You need to use ostream or ofstream to write/ouput data.
You use istream or ifstream to read/input data.

Example:
#include <fstream>
#include <iostream>
#include <string>

void SomeFunction1(void)
{
std::ofstream m("test.txt");
CString data = "test 1";
m << (LPCTSTR)data;
m.close();
}

void SomeFunction2(void)
{
std::ofstream m("test.txt");
std::string data = "test 2";
m << data;
m.close();
}

If you want to read and write data, you can use fstream.

And as I previously stated, to conver a std::string to CString you can use the following method:
string szdata1 = "hello world";
CString szdata2 = szdata1.c_str();
0
 
LVL 30

Expert Comment

by:Axter
ID: 6262600
If you need to write to the stream, here are some examples:

void SomeFunction3(void)
{
     std::ifstream m("test.txt");
     std::string data;//Read complete line
     std::getline(m,data);
     m.close();
}

void SomeFunction4(void)
{
     std::ifstream m("test.txt");
     std::string data;
     m >> data;//Read until reaches first space
     m.close();
}

void SomeFunction5(void)
{
     std::ifstream m("test.txt");
     std::string data;
     for(;;) //Read everything
    {
          std::string tmp = "";
          std::getline(m,tmp);
          if (m.eof()) break;
          data += tmp + "\n";
    }
     m.close();
}
0
 
LVL 23

Expert Comment

by:Roshan Davis
ID: 9490246
No comment has been added lately, so it's time to clean up this TA.
I will leave a recommendation in the Cleanup topic area that this question is:

Answered by: Axter, migel (points to be split)

Please leave any comments here within the next seven days.

PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!

Roshan Davis
EE Cleanup Volunteer
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