why can't I use string???

This is a discussion on why can't I use string??? within the Windows Programming forums, part of the Platform Specific Boards category; hello, well I have been struggling with something that makes absolutely no sense to me for the past hour now. ...

  1. #1
    Madly in anger with you
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    why can't I use string???

    hello,
    well I have been struggling with something that makes absolutely no sense to me for the past hour now.

    for some reason, my compiler (MSVC++ 6.0) will not let me use the C++ string class. I have included the string header, but am guessing it is missing alot of declarations or something.

    Firstly, I tried using a C-style null terminated char array for a string. then I found MSVC++ does not have the strings.h. so now I try to use the C++ string class, and get "undeclared identifier" on the line that my identifier exists on . please take a look at this and try to point out something that I am doing wrong (I am guessing I'll have to write my own string class and include it in a new header to fix it ):

    Code:
    #include "stdafx.h"
    #include "resource.h"
    #include <stdio.h>
    #include <windows.h>
    #include <commdlg.h>
    #include <string>
    
    BOOL CALLBACK DlgProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
    	string szFileName1("");
            string szFileName2("");
    that would declare strings with the identifiers of "szFileName1" and "szFileName2"? correct???? I am using the ("") for safety and clarity purposes. so then I try this:

    Code:
    #include "stdafx.h"
    #include "resource.h"
    #include <stdio.h>
    #include <windows.h>
    #include <commdlg.h>
    #include <string>
    
    BOOL CALLBACK DlgProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
    	char szFileName1[] = "";
            char szFileName2[] = "";
            string F1(szFileName1);
            string F2(szFileName2);
    and I still get the undeclared identifier error . I read up on the error and its description says its usually caused by a variable declaration with no type specified. but I don't see where there are ANY missing types (not unless they are in the included string.h like I said), the variables you see in first example should be of type string, and the second example should be null terminated char arrays (c-style strings) which then get defined as strings called F1 and F2. so can someone here please tell me what the heck I am doing wrong ????

    thank you in advance

  2. #2
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    A quick glance through the C++ forum tells me that the string class is in the std namespace. So, you either declare the variables as std::string or put "using namespace std;" underneath your includes.

  3. #3
    Registered User kryptkat's Avatar
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    dot h aka .h is a c string header not cpp. You have to compile the file as a cpp file for it to work.

    Code:
    char teststr1[] = { "abcdefghijklmnopqrstuvwxyz"  } ;
    works fine for c.

    edit to add

    You can not use cpp in c.
    Last edited by kryptkat; 12-23-2005 at 05:18 PM.

  4. #4
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    must be something else

    thanks kryptkat! that was my problem (didn't know .h made any difference for dev environment included headers ).
    Last edited by Bleech; 12-23-2005 at 05:23 PM.

  5. #5
    carry on JaWiB's Avatar
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    Firstly, I tried using a C-style null terminated char array for a string. then I found MSVC++ does not have the strings.h. so now I try to use the C++ string class, and get "undeclared identifier" on the line that my identifier
    Try:
    Code:
    #include <cstring>
    But if you're using C++ then it might be best to get used to std::string's
    "Think not but that I know these things; or think
    I know them not: not therefore am I short
    Of knowing what I ought."
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  6. #6
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    then I found MSVC++ does not have the strings.h
    That's because the C header is <string.h>, not <strings.h>.

  7. #7
    Frequently Quite Prolix dwks's Avatar
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    The standard C header files are available in C++. You just drop the .h and add a leading c. So <stdio.h> becomes <cstdio>.
    A quick glance through the C++ forum tells me that the string class is in the std namespace. So, you either declare the variables as std::string or put "using namespace std;" underneath your includes.
    Or you can use
    Code:
    using std::string;
    which is what I prefer.
    dwk

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