STL String and member funcs

This is a discussion on STL String and member funcs within the C++ Programming forums, part of the General Programming Boards category; I'm new to the STL string (all of STL for that matter). I just learned that a NULL string can't ...

  1. #1
    Nix Phoeni
    Guest

    Angry STL String and member funcs

    I'm new to the STL string (all of STL for that matter). I just learned that a NULL string can't be assigned in the copy constructor, and since I'm still getting errors, I'm guessing in the operator = as well. Is there any way to check if I'm going to be assigning a NULL string to another string? I tried

    if(name=="") return;
    else file = name;

    but it didn't really work (name had an address of 0xdddddddd). What can I do? Any help or a website I could find would be appreciated.

  2. #2
    Toaster Zach L.'s Avatar
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    Aug 2001
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    2,686
    Use the strcmp() function from the <cstring> header. For example:
    Code:
    #include <cstring>
    #include <string>
    using namespace std;
    
    int main()
    {
        string file;
        char* name = "Some string.";
    
        if(strcmp(name, "") == 0)
            return 0;
        else
            file = name;
    }
    The word rap as it applies to music is the result of a peculiar phonological rule which has stripped the word of its initial voiceless velar stop.

  3. #3
    Registered User NixPhoeni's Avatar
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    Aug 2001
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    10

    Unhappy not quite...

    Sorry, I wasn't clear. In this code

    if(name=="") return;
    else file = name;

    both name and file are strings. Is there some way to check if name is NULL?
    -Joe
    -------------------------------------------
    To understand a program you must become both the machine and the program.
    --Alan Perlis

  4. #4
    zen
    zen is offline
    of Zen Hall zen's Avatar
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    To get the length you can use strings length member function -

    if(name.length()==0) return;
    else file = name;

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