const char[] or string?

This is a discussion on const char[] or string? within the C++ Programming forums, part of the General Programming Boards category; Hey guys i have a quick question. Im currently using a const char to print out a message that is ...

  1. #1
    Sweet
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    const char[] or string?

    Hey guys i have a quick question. Im currently using a const char to print out a message that is printed to the screen alot eg.
    Code:
    const char welcomeMsg[6]"Hello";
    should i use the string class instead or is it a matter of preferance?
    Woop?

  2. #2
    mustang benny bennyandthejets's Avatar
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    Because the message is constant, ie, it's not supposed to change, an STL string would be a bit of overkill. When you need to parse, split, or grow a string, use STL.
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  3. #3
    Sweet
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    Ok cool thanks Benny
    Woop?

  4. #4
    Code Goddess Prelude's Avatar
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    >Because the message is constant, ie, it's not supposed to change, an STL string would be a bit of overkill.
    Even if it's not supposed to change, the member functions and overloaded operators of the string class can be mighty useful. Consider the following method:
    Code:
    const char welcomeMsg[] = "Hello";
    Now, the advantage of strings is diminished because to compare with welcomeMsg (assuming the non-const strings are declared std::string X;) you still must include <cstring> and use strcpy and friends:
    Code:
    if (strcpy(X.c_str(), welcomeMsg) == 0) {
      // Equal
    }
    The same goes for every other operation with welcomeMsg that requires a C-style string function. On the other hand, if welcomeMsg were declared as such:
    Code:
    const std::string welcomeMsg("Hello");
    The complex comparison for equality would simply be:
    Code:
    if (X == welcomeMsg) {
      // Equal
    }
    And the same advantage is true for any other overloaded operators. Another advantage is that now you can work easily with welcomeMsg if the need arises without resorting to C-style string functions or hand-rolled functions if the C library doesn't support what you want in some fashion. The C++ string class has a respectable number of member functions that are useful even with const strings.

    Conclusion? Don't mix C and C++ strings when you can avoid it. This almost always results in not using C-style strings and a considerable improvement in the quality and robustness of the code.
    Last edited by Prelude; 07-10-2004 at 08:34 AM.
    My best code is written with the delete key.

  5. #5
    carry on JaWiB's Avatar
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    Code:
    if (strcpy(X.c_str(), welcomeMsg) == 0) {
      // Equal
    }
    Don't you mean strcmp()?
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    Indeed, that code compares a char pointer with 0, which has to be considered an error.

  7. #7
    Code Goddess Prelude's Avatar
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    >Don't you mean strcmp()?
    Yes. My fingers were running on autopilot.
    My best code is written with the delete key.

  8. #8
    mustang benny bennyandthejets's Avatar
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    I still think it's overkill for a simple welcome message.
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  9. #9
    Sweet
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    ya i have no need to compare, add to or anything like that im just using it so i don't have to type so much
    Woop?

  10. #10
    Code Goddess Prelude's Avatar
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    >I still think it's overkill for a simple welcome message.
    The C++ string class was designed to be comparable in size and speed with C-style strings. Also, because of the hidden implementation, library writers have quite a bit of freedom in making std::string superior to C-style strings in the way of performance and space costs. I think your hesitation is unfounded.
    My best code is written with the delete key.

  11. #11
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    I think there are some advantages to localization if he stored the data in a central location such as a resource(etc.) There, I think he'd pretty much have to store c-style strings. Besides, even when writing code such as std::string("Hello") the "Hello" characters will be stored as static c-style array.

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