How to Parse a CSV formatted text file

Discussion in 'C++' started by Ram Laxman, Feb 7, 2004.

  1. Ram Laxman

    Ram Laxman Guest

    Hi all,
    I have a text file which have data in CSV format.
    "empno","phonenumber","wardnumber"
    12345,2234353,1000202
    12326,2243653,1000098
    Iam a beginner of C/C++ programming.
    I don't know how to tokenize the comma separated values.I used strtok
    function reading line by line using fgets.but it gives some weird
    behavior.It doesnot stripout the "" fully.Could any body have sample
    code for the same so that it will be helfful for my reference?

    Ram Laxman



    Ram Laxman
    Ram Laxman, Feb 7, 2004
    #1
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  2. Ram Laxman

    Phlip Guest

    Ram Laxman wrote:

    > I have a text file which have data in CSV format.
    > "empno","phonenumber","wardnumber"
    > 12345,2234353,1000202
    > 12326,2243653,1000098
    > Iam a beginner of C/C++ programming.
    > I don't know how to tokenize the comma separated values.I used strtok
    > function reading line by line using fgets.but it gives some weird
    > behavior.It doesnot stripout the "" fully.Could any body have sample
    > code for the same so that it will be helfful for my reference?


    Parsing is tricky. Consider these rules:

    - \n is absolute. All lines must be unbroken
    - "" precedes , - so commas inside strings are text, not delimiters
    - quotes inside "" need an escape, either \n or ""
    - escapes need escapes - \\ is \

    Try this project to learn more:

    http://c2.com/cgi/wiki?MsWindowsResourceLint

    First, we express those rules (one by one) as test cases:

    TEST_(TestCase, pullNextToken_comma)
    {

    Source aSource("a , b\nc, \n d");

    string
    token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("a", token);
    token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("b", token);
    token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("c", token);
    token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("d", token);
    token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("", token);
    // EOF!

    }

    struct
    TestTokens: TestCase
    {

    void
    test_a_b_d(string input)
    {
    Source aSource(input);
    string
    token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("a", token);
    token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("b", token);
    // token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("c",
    token);
    token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("d", token);
    token = aSource.pullNextToken(); CPPUNIT_ASSERT_EQUAL("", token);
    // EOF!
    }

    };

    TEST_(TestTokens?, elideComments)
    {
    test_a_b_d("a b\n //c\n d");
    test_a_b_d("a b\n//c \n d");
    test_a_b_d("a b\n // c \"neither\" \n d");
    test_a_b_d("a b\n // c \"neither\" \n d//");
    test_a_b_d("//\na b\n // c \"neither\" \n d//");
    test_a_b_d("//c\na b\n // c \"neither\" \n d//");
    test_a_b_d("// c\na b\n // c \"neither\" \n d//");
    test_a_b_d("//c \na b\n // c \"neither\" \n d//");
    test_a_b_d("// \na b\n // c \"neither\" \n d//");
    test_a_b_d(" // \na b\n // c \"neither\" \n d//");
    }

    TEST_(TestTokens?, elideStreamComments)
    {
    test_a_b_d("a b\n /*c*/\n d");
    test_a_b_d("a b\n/*c*/ \n d");
    test_a_b_d("a b\n /* c \"neither\" */\n d");
    test_a_b_d("a b\n /* c \"neither\" \n */ d//");
    test_a_b_d("//\na b\n /* c \"neither\" */ \n d/**/");
    test_a_b_d("//c\na b\n // c \"neither\" \n d/* */");
    test_a_b_d("/* c\n*/a b\n // c \"neither\" \n d//");
    test_a_b_d("//c \na b\n // c \"neither\" \n d//");
    test_a_b_d("// \na b\n // c \"neither\" \n d//");
    test_a_b_d(" // \na b\n // c \"neither\" \n d//");
    }

    Those tests re-use the fixture test_a_b_d() to ensure that every one of
    those strings parse into a, b, & d, skipping (for whatever reason) c.

    You will need tests that show slightly different behaviors. But write your
    tests one at a time. I wrote every single line you see here, essentially in
    order, and got it to work before adding the next line. Don't write all your
    tests at once, because when programming you should never go more than 1~10
    edits before passing all tests.

    Now here's the source of Source (which means "source of tokens"):

    class
    Source
    {
    public:
    Source(string const & rc = ""):
    m_rc(rc),
    m_bot(0),
    m_eot(0)
    {}

    void setResource(string const & rc) { m_rc = rc; }
    size_type getBOT() { return m_bot; }
    string const & getPriorToken() { return m_priorToken; }
    string const & getCurrentToken() { return m_currentToken; }

    string const &
    pullNextToken()
    {
    m_priorToken = m_currentToken;
    extractNextToken();
    return m_currentToken;
    }

    size_type
    getLineNumber(size_type at)
    {
    size_type lineNumber = 1;

    for(size_type idx(0); idx < at; ++idx)
    if ('\n' == m_rc[idx])
    ++lineNumber;

    return lineNumber;
    }

    string
    getLine(size_type at)
    {
    size_type bol = m_rc.rfind('\n', at);
    if (string::npos == bol) bol = 0; else ++bol;
    size_type eol = m_rc.find('\n', at);
    if (string::npos == eol) eol = m_rc.length(); else ++eol;
    return m_rc.substr(bol, eol - bol);
    }

    private:

    string const &
    extractNextToken()
    {
    char static const delims[] = " \t\n,";

    m_bot = m_rc.find_first_not_of(delims, m_eot);

    if (string::npos == m_bot)
    m_currentToken = "";
    else if (m_rc[m_bot] == '"')
    m_currentToken = parseString();
    else if (m_rc.substr(m_bot, 2) == "//")
    {
    if (skipUntil("\n"))
    return extractNextToken();
    }
    else if (m_rc.substr(m_bot, 2) == "/*")
    {
    if (skipUntil("*/"))
    return extractNextToken();
    }
    /* else if (m_rc.substr(m_bot, 1) == "#")
    {
    string line = getLine(m_bot);
    size_type at(0);
    while(isspace(line[at]) && at < line.size()) ++at;


    if ('#' == line[at])
    {
    m_eot = m_bot + 1;
    if (skipUntil("\n"))
    return extractNextToken();
    }
    }*/
    else
    {
    m_eot = m_rc.find_first_of(" \n,/", m_bot);
    m_currentToken = m_rc.substr(m_bot, m_eot - m_bot);
    }

    if ('#' == m_currentToken[0])
    {
    // assert(m_rc.substr(m_bot, 1) == "#");
    string line = getLine(m_bot);
    size_type at(0);
    while(isspace(line[at]) && at < line.size()) ++at;

    if ('#' == line[at])
    {
    --m_eot;
    if (skipUntil("\n"))
    return extractNextToken();
    }
    }
    return m_currentToken;
    }

    bool
    skipUntil(char const * delimiter)
    {
    m_eot = m_rc.find(delimiter, m_eot + 1);

    if (string::npos == m_eot)
    {
    m_currentToken = "";
    return false;
    }
    m_eot += strlen(delimiter);
    return true;
    }

    char
    parseStringChar()
    {
    if (m_rc[m_eot] == '\\')
    {
    m_eot += 1;
    char escapee(m_rc[m_eot++]);

    switch (escapee)
    {
    case 'n' : return '\n';
    case 'r' : return '\r';
    case 't' : return '\t';
    case '0' : return '\0';
    case '\\': return '\\';
    case 'a' : return '\a';
    default : // TODO \x, \v \b, \f
    if (isdigit(escapee))
    {
    string slug = m_rc.substr(m_eot - 1, 3);
    return char(strtol(slug.c_str(), NULL, 8));
    }
    else
    //assert(false);
    return escapee;
    }
    }
    else if (m_rc[m_eot] == '"' && m_rc[m_eot+1] == '"')
    m_eot++;

    return m_rc[m_eot++];
    }

    string
    parseString()
    {
    m_eot = m_bot + 1;
    string z;

    while ( m_eot < m_rc.length() &&
    ( m_rc[m_eot] != '"' ||
    m_rc[m_eot + 1] == '"' ) )
    z += parseStringChar();

    if (m_eot < m_rc.length())
    m_eot += 1;

    return z;
    }

    string m_rc;
    size_type m_bot;
    size_type m_eot;
    string m_priorToken;
    string m_currentToken;
    };

    That looks really ugly & long, because it hides so much behind such a narrow
    interface. (I don't know if I copied all of it in, either.) But it
    demonstrates (possibly) correct usage of std::string and std::vector.

    Do not copy my source into your editor and try to run it. It will not parse
    CVS. Start your project like this:

    #include <assert.h>
    #include <string>
    #include <vector>
    typedef std::vector<std::string> strings_t;

    strings_t parse(std::string input)
    {
    strings_t result;
    return result;
    }

    int main()
    {
    assert("a" == parse("a,b")[0]);
    }

    If that compiles, it >will< crash if you run it.

    Now fix parse() so that it _only_ does not crash, and passes this test. Make
    the implementation as stupid as you like.

    Then add a test:

    assert("a" == parse("a,b")[0]);
    assert("b" == parse("a,b")[1]);

    Keep going. Make the implementation just a little better after each test.
    Write a set of tests for each of the parsing rules I listed. When the new
    parse() function is full-featured, put it to work in your program.

    All programs should be written by generating long lists of simple tests like
    this. That keeps the bug count very low, and prevents wasting hours and
    hours with a debugger.

    --
    Phlip
    http://www.xpsd.org/cgi-bin/wiki?TestFirstUserInterfaces
    Phlip, Feb 7, 2004
    #2
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  3. Ram Laxman

    Phlip Guest

    Willem wrote:

    > Ram wrote:
    > ) Hi all,
    > ) I have a text file which have data in CSV format.
    > ) "empno","phonenumber","wardnumber"
    > ) 12345,2234353,1000202
    > ) 12326,2243653,1000098
    > ) Iam a beginner of C/C++ programming.
    > ) I don't know how to tokenize the comma separated values.I used strtok
    > ) function reading line by line using fgets.but it gives some weird
    > ) behavior.It doesnot stripout the "" fully.Could any body have sample
    > ) code for the same so that it will be helfful for my reference?
    >
    > Here's a tip: Look for a library that scans CSV files.


    Hi Willem! Welcome to the first hard projects of this semester. So far, a
    professor somewhere has assumed their class was reading the right chapters
    in their tutorial, and has hit them with the first non-Hello World project.

    Someone just posted the same question to news:comp.programming .

    --
    Phlip
    http://www.xpsd.org/cgi-bin/wiki?TestFirstUserInterfaces
    Phlip, Feb 7, 2004
    #3
  4. Ram Laxman

    Willem Guest

    Ram wrote:
    ) Hi all,
    ) I have a text file which have data in CSV format.
    ) "empno","phonenumber","wardnumber"
    ) 12345,2234353,1000202
    ) 12326,2243653,1000098
    ) Iam a beginner of C/C++ programming.
    ) I don't know how to tokenize the comma separated values.I used strtok
    ) function reading line by line using fgets.but it gives some weird
    ) behavior.It doesnot stripout the "" fully.Could any body have sample
    ) code for the same so that it will be helfful for my reference?

    Here's a tip: Look for a library that scans CSV files.

    And if you really want to do it yourself, you really don't want to be using
    stuff like strtok. Assuming you have one complete line in memory, you're
    better off searching for the commas (and quotes) yourself, that's really
    not so hard. Just put NULs where the commas are, and point to the
    beginning of the strings (just after the comma). You can then pass these
    pointers as strings to another parsing routine that turns stuff without
    quotes into integers, and stuff with quotes into strings or whatever.


    SaSW, Willem
    --
    Disclaimer: I am in no way responsible for any of the statements
    made in the above text. For all I know I might be
    drugged or something..
    No I'm not paranoid. You all think I'm paranoid, don't you !
    #EOT
    Willem, Feb 7, 2004
    #4
  5. Ram Laxman

    Mike Wahler Guest

    "Ram Laxman" <> wrote in message
    news:...
    > Hi all,
    > I have a text file which have data in CSV format.
    > "empno","phonenumber","wardnumber"
    > 12345,2234353,1000202
    > 12326,2243653,1000098
    > Iam a beginner of C/C++ programming.
    > I don't know how to tokenize the comma separated values.I used strtok
    > function reading line by line using fgets.but it gives some weird
    > behavior.It doesnot stripout the "" fully.Could any body have sample
    > code for the same so that it will be helfful for my reference?
    >
    > Ram Laxman


    #include <cstdlib>
    #include <fstream>
    #include <ios>
    #include <iomanip>
    #include <iostream>
    #include <sstream>
    #include <string>

    int main()
    {
    std::ifstream ifs("csv.txt");
    if(!ifs)
    {
    std::cerr << "Cannot open input\n";
    return EXIT_FAILURE;
    }

    const std::streamsize width(15);
    std::cout << std::left;

    std::string line;
    while(std::getline(ifs, line))
    {
    std::string tok1;
    std::istringstream iss(line);
    while(std::getline(iss, tok1, ','))
    {
    if(tok1.find('"') != std::string::npos)
    {
    std::string tok2;
    std::istringstream iss(tok1);
    while(std::getline(iss, tok2, '"'))
    {
    if(!tok2.empty())
    std::cout << std::setw(width) << tok2;
    }
    }
    else
    std::cout << std::setw(width) << tok1;

    std::cout << ' ';

    }
    std::cout << " \n";
    }

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

    return 0;
    }

    Input file:

    "empno","phonenumber","wardnumber"
    12345,2234353,1000202
    12326,2243653,1000098



    Output:

    empno phonenumber wardnumber
    12345 2234353 1000202
    12326 2243653 1000098



    -Mike
    Mike Wahler, Feb 7, 2004
    #5
  6. Ram Laxman

    Phlip Guest

    Mike Wahler wrote:

    > #include <cstdlib>


    Hi Mike!

    I just wanted to be the first to remind you that the FAQ advises against
    doing others' homework - fun though it may be. (Advising the newbie to throw
    in a few Design Patterns is better sport, of course...)

    --
    Phlip
    http://www.xpsd.org/cgi-bin/wiki?TestFirstUserInterfaces
    Phlip, Feb 7, 2004
    #6
  7. Ram Laxman

    Jon Bell Guest

    In article <mgaVb.17848$>,
    Mike Wahler <> wrote:

    [code snipped]

    >Input file:
    >
    >"empno","phonenumber","wardnumber"
    >12345,2234353,1000202
    >12326,2243653,1000098


    Try changing the first line so one of the tokens contains a comma, e.g.

    "empno","phone, number","wardnumber"

    ;-)

    I started to work on a solution, too, and then I thought about embedded
    commas, and went, "uh oh..."

    --
    Jon Bell <> Presbyterian College
    Dept. of Physics and Computer Science Clinton, South Carolina USA
    Jon Bell, Feb 7, 2004
    #7
  8. Ram Laxman

    Mike Wahler Guest

    "Phlip" <> wrote in message
    news:YtaVb.19462$...
    > Mike Wahler wrote:
    >
    > > #include <cstdlib>

    >
    > Hi Mike!
    >
    > I just wanted to be the first to remind you that the FAQ advises against
    > doing others' homework - fun though it may be.


    Yes, I realize that.

    > (Advising the newbie to throw
    > in a few Design Patterns is better sport, of course...)


    I very much doubt that the code would be accepted 'as is'
    by an instructor -- unless the student can explain it --
    in which case he would have actually studied and learned... :)
    Anyway, it seems that OP isn't quite sure whether he's learning
    C or C++.

    -Mike
    Mike Wahler, Feb 7, 2004
    #8
  9. Ram Laxman

    Mike Wahler Guest

    "Jon Bell" <> wrote in message
    news:c03c7s$mq0$...
    > In article <mgaVb.17848$>,
    > Mike Wahler <> wrote:
    >
    > [code snipped]
    >
    > >Input file:
    > >
    > >"empno","phonenumber","wardnumber"
    > >12345,2234353,1000202
    > >12326,2243653,1000098

    >
    > Try changing the first line so one of the tokens contains a comma, e.g.
    >
    > "empno","phone, number","wardnumber"
    >
    > ;-)
    >
    > I started to work on a solution, too, and then I thought about embedded
    > commas, and went, "uh oh..."


    Well, yes I did think about bad input, but thought I'd leave that
    to the OP. IOW I gave a very 'literal' answer that only addressed
    the exact input cited by the OP. :)


    -Mike
    Mike Wahler, Feb 7, 2004
    #9
  10. Ram Laxman

    Jon Bell Guest

    In article <vGaVb.17879$>,
    Mike Wahler <> wrote:
    >
    >Well, yes I did think about bad input, but thought I'd leave that
    >to the OP. IOW I gave a very 'literal' answer that only addressed
    >the exact input cited by the OP. :)


    It would be interesting to find out if the instructor actually intended
    the students to go whole hog and deal with embedded commas, escaped
    quotes, etc. If it's an introductory programming course, it's quite
    possible they don't need to worry about those details for the purposes of
    the assignment.

    --
    Jon Bell <> Presbyterian College
    Dept. of Physics and Computer Science Clinton, South Carolina USA
    Jon Bell, Feb 7, 2004
    #10
  11. Ram Laxman

    Derk Gwen Guest

    (Ram Laxman) wrote:
    # Hi all,
    # I have a text file which have data in CSV format.
    # "empno","phonenumber","wardnumber"
    # 12345,2234353,1000202
    # 12326,2243653,1000098
    # Iam a beginner of C/C++ programming.
    # I don't know how to tokenize the comma separated values.I used strtok
    # function reading line by line using fgets.but it gives some weird
    # behavior.It doesnot stripout the "" fully.Could any body have sample
    # code for the same so that it will be helfful for my reference?

    This is probably a type 3 language, so you can probably use a finite
    state machine. If you're just beginning, that can be an intimidating
    bit of jargon, but FSMs are actually easy to understand, and if you
    want to be a programmer, you have to understand them. They pop up all
    over the place.

    You can #defines to abstract the FSM with something like

    #define FSM(name) static int name(FILE *file) {int ch=0,m=0,n=0; char *s=0;
    #define endFSM return -1;}

    #define state(name) name: ch = fgetc(stdin); e_##name: switch (ch) {
    #define endstate } return -1;

    #define is(character) case character:
    #define any default:
    #define next(name) ;goto name
    #define emove(name) ;goto e_##name;
    #define final(name,value) name: e_##name: free(s); return value;

    #define shift ;if (n+1>=m) {m = 2*(n+1); s = realloc(s,m);} s[n++] = ch;
    #define discard ;m = n = 0; s = 0;
    #define dispose ;free(s) discard



    static void got_empno(char *s);
    static void got_phonenumber(char *s);
    static void got_wardnumber(char *s);
    static void got_csventry(void);

    FSM(csv_parser)
    state(empno)
    is('"') next(quoted_empno)
    is(EOF) next(at_end)
    is(',') got_empno(s) discard next(phonenumber)
    any shift next(empno)
    endstate
    state(quoted_empno)
    is('"') next(empno)
    is(EOF) next(at_end_in_string)
    any shift next(empno)
    endstate
    state(phonenumber)
    is('"') next(quoted_phonenumber)
    is(EOF) next(at_end_in_entry)
    is(',') got_phonenumber(s) discard next(wardnumber)
    any shift next(phonenumber)
    endstate
    state(quoted_phonenumber)
    is('"') next(phonenumber)
    is(EOF) next(at_end_in_string)
    any shift next(phonenumber)
    endstate
    state(wardnumber)
    is('"') next(quoted_wardnumber)
    is(EOF)
    got_wardnumber(s); got_csventry() discard
    next(at_end)
    is('\n')
    got_wardnumber(s); got_csventry() discard
    next(empno)
    is(',') got_wardnumber(s) discard next(unexpected_field)
    any shift next(wardnumber)
    endstate
    state(quoted_wardnumber)
    is('"') next(wardnumber)
    is(EOF) next(at_end_in_string)
    any shift next(wardnumber)
    endstate
    final(at_end,0)
    final(at_end_in_string,1)
    final(unexpected_field,2)
    endFSM

    ....
    int rc = csv_parser(stdin);
    // calls
    // got_empno(empno-string)
    // got_phonenumber(phonenumber-string)
    // got_wardnumber(wardnumber-string)
    // got_csventry()
    // for each entry
    switch (rc) {
    case -1: fputs("parser failure\n",stderr); break;
    case 1: fputs("end of file in a string\n",stderr); break;
    case 2: fputs("too many fields\n",stderr); break;
    }
    ....

    --
    Derk Gwen http://derkgwen.250free.com/html/index.html
    I have no idea what you just said.
    I get that alot.
    Derk Gwen, Feb 7, 2004
    #11
  12. Ram Laxman

    Jack Klein Guest

    On Sat, 07 Feb 2004 18:38:10 GMT, "Mike Wahler"
    <> wrote in comp.lang.c:

    >
    > "Ram Laxman" <> wrote in message
    > news:...
    > > Hi all,
    > > I have a text file which have data in CSV format.
    > > "empno","phonenumber","wardnumber"
    > > 12345,2234353,1000202
    > > 12326,2243653,1000098
    > > Iam a beginner of C/C++ programming.
    > > I don't know how to tokenize the comma separated values.I used strtok
    > > function reading line by line using fgets.but it gives some weird
    > > behavior.It doesnot stripout the "" fully.Could any body have sample
    > > code for the same so that it will be helfful for my reference?
    > >
    > > Ram Laxman

    >
    > #include <cstdlib>
    > #include <fstream>
    > #include <ios>
    > #include <iomanip>
    > #include <iostream>
    > #include <sstream>
    > #include <string>


    [snip]

    Mike, please do NOT post C++ code to messages crossposted to
    comp.lang.c.

    Thanks

    --
    Jack Klein
    Home: http://JK-Technology.Com
    FAQs for
    comp.lang.c http://www.eskimo.com/~scs/C-faq/top.html
    comp.lang.c++ http://www.parashift.com/c -faq-lite/
    alt.comp.lang.learn.c-c++
    http://www.contrib.andrew.cmu.edu/~ajo/docs/FAQ-acllc.html
    Jack Klein, Feb 7, 2004
    #12
  13. Ram Laxman

    bartek Guest

    (Ram Laxman) wrote in
    news::

    > Hi all,
    > I have a text file which have data in CSV format.
    > "empno","phonenumber","wardnumber"
    > 12345,2234353,1000202
    > 12326,2243653,1000098
    > Iam a beginner of C/C++ programming.
    > I don't know how to tokenize the comma separated values.I used strtok
    > function reading line by line using fgets.but it gives some weird
    > behavior.It doesnot stripout the "" fully.Could any body have sample
    > code for the same so that it will be helfful for my reference?
    >


    Check out the amazing Spirit framework.
    It's available from Boost libraries: http://www.boost.org
    bartek, Feb 7, 2004
    #13
  14. On 7 Feb 2004 09:39:14 -0800, in comp.lang.c ,
    (Ram Laxman) wrote:

    >Hi all,
    > I have a text file which have data in CSV format.
    >"empno","phonenumber","wardnumber"
    >12345,2234353,1000202
    >12326,2243653,1000098
    >Iam a beginner of C/C++ programming.
    >I don't know how to tokenize the comma separated values.I used strtok
    >function reading line by line using fgets.but it gives some weird
    >behavior.


    yes, you need to handle that sort of stuff yourself. Personally I'd
    use strtok on this sort of data, since embedded commas should not
    exist. Consider the 1st line a special case.

    --
    Mark McIntyre
    CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
    CLC readme: <http://www.angelfire.com/ms3/bchambless0/welcome_to_clc.html>


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    Mark McIntyre, Feb 8, 2004
    #14
  15. Ram Laxman

    Joe Wright Guest

    Mark McIntyre wrote:
    >
    > On 7 Feb 2004 09:39:14 -0800, in comp.lang.c ,
    > (Ram Laxman) wrote:
    >
    > >Hi all,
    > > I have a text file which have data in CSV format.
    > >"empno","phonenumber","wardnumber"
    > >12345,2234353,1000202
    > >12326,2243653,1000098
    > >Iam a beginner of C/C++ programming.
    > >I don't know how to tokenize the comma separated values.I used strtok
    > >function reading line by line using fgets.but it gives some weird
    > >behavior.

    >
    > yes, you need to handle that sort of stuff yourself. Personally I'd
    > use strtok on this sort of data, since embedded commas should not
    > exist. Consider the 1st line a special case.
    >

    I don't know of a 'Standard' defining .csv but this is normal output
    from Visual FoxPro..

    first,last
    "Mac "The Knife" Peter","Boswell, Jr."

    But strangely, Excel reads it back wrong. Go figure.
    "Failure is not an option. With M$ it is bundled with every package."

    The format started with dBASE I think and goes something like this..

    Fields are alphanumerics separated by commas. Fields of type 'Character'
    are further delimited with '"' so that they might contain comma and '"'
    itself. The Rules are something like this..

    The first field begins with the first character on the line.
    Fields end at a naked ',' comma or '\n' newline.
    Delimited fields begin with '"' and end with '"' and comma or newline.
    The delimiters are not a literal part of the field. Any comma or '"'
    within the delimiters are literals.

    --
    Joe Wright http://www.jw-wright.com
    "Everything should be made as simple as possible, but not simpler."
    --- Albert Einstein ---
    Joe Wright, Feb 8, 2004
    #15
  16. On Sun, 08 Feb 2004 14:43:05 GMT, in comp.lang.c , Joe Wright
    <> wrote:

    >Mark McIntyre wrote:
    >>
    >>
    >> yes, you need to handle that sort of stuff yourself. Personally I'd
    >> use strtok on this sort of data, since embedded commas should not
    >> exist. Consider the 1st line a special case.
    >>

    >I don't know of a 'Standard' defining .csv but this is normal output
    >from Visual FoxPro..


    snip example w/ embedded commas.

    Interesting, but hte OP's data was employee numbers, phone numbers and
    ward numbers. I find Occam's Razor to be efficient in such cases.

    --
    Mark McIntyre
    CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
    CLC readme: <http://www.angelfire.com/ms3/bchambless0/welcome_to_clc.html>


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    Mark McIntyre, Feb 8, 2004
    #16
  17. Ram Laxman

    David Harmon Guest

    On Sun, 08 Feb 2004 14:43:05 GMT in comp.lang.c++, Joe Wright
    <> was alleged to have written:
    >I don't know of a 'Standard' defining .csv but this is normal output
    >from Visual FoxPro..
    >
    >first,last
    >"Mac "The Knife" Peter","Boswell, Jr."
    >
    >But strangely, Excel reads it back wrong.


    Excel expects quotes within the field to be doubled. In fact, I would
    go so far as to say FoxPro is wrong.

    More lenient parsing would recognize a quote not followed by a comma or
    newline as contained within the field. This creates some ambiguities,
    since quoted fields can also contain newline.

    There is no standard, but see http://www.wotsit.org/download.asp?f=csv
    David Harmon, Feb 8, 2004
    #17
  18. > I have a text file which have data in CSV format.

    What *IS* CSV format? The following "definition by example"
    isn't very complete.

    >"empno","phonenumber","wardnumber"
    >12345,2234353,1000202
    >12326,2243653,1000098


    Your examples do not handle the corner cases where a string
    contains commas, quotes, and/or newlines. If your definition
    introduces an "escape" character, also worry about strings
    consisting of several of those characters. Also, can single
    quotes be used in place of double quotes? Can a single quote
    match a double quote or vice versa?

    Also it isn't explained what isn't a valid CSV format. How
    about these:

    ,,,,,,,,,,,,,,,,,,,,
    ,""""""""""""""""""""""""""",
    ,"""""""""""""""""""""""""""",
    ,""""""""""""""""""""""""""""",
    "\\\\\\\\\\\\\\\\\"
    "\\\\\\\\\\\\\\\\\\"
    "\\\\\\\\\\\\\\\\\\\"
    """""""""""""""""""""""
    """"""""""""""""""""""""
    """""""""""""""""""""""""
    """"""""""""""""""""""""""

    Gordon L. Burditt
    Gordon Burditt, Feb 9, 2004
    #18
  19. Since this is mostly about C++ I removed crossposting to non-C++ groups.

    bartek <2.pl> wrote:
    > (Ram Laxman) wrote in
    > news::
    > > Iam a beginner of C/C++ programming.


    > Check out the amazing Spirit framework.


    It took me something like half a day to make any sense at all out of the
    indeed amazing Spirit framework - and I personally don't consider myself
    really a beginner of C/C++ programming... Of course, we might consider
    providing a full-fledged solution using Spirit as this would certainly
    disqualify as a potential solution to a homework assignment.
    --
    <mailto:> <http://www.dietmar-kuehl.de/>
    Phaidros eaSE - Easy Software Engineering: <http://www.phaidros.com/>
    Dietmar Kuehl, Feb 9, 2004
    #19
  20. Joe Wright <> wrote:
    > I don't know of a 'Standard' defining .csv but this is normal output
    > from Visual FoxPro..
    >
    > first,last
    > "Mac "The Knife" Peter","Boswell, Jr."
    >
    > But strangely, Excel reads it back wrong. Go figure.
    > "Failure is not an option. With M$ it is bundled with every package."


    So, you are saying this is not at all a homework assignment but rather a
    request from a Microsoft engineer asking for correct code dealing with
    their files?
    --
    <mailto:> <http://www.dietmar-kuehl.de/>
    Phaidros eaSE - Easy Software Engineering: <http://www.phaidros.com/>
    Dietmar Kuehl, Feb 9, 2004
    #20
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