Passing a string to a constructor?

This is a discussion on Passing a string to a constructor? within the C++ Programming forums, part of the General Programming Boards category; Okay so I'm currently starting to work in SFML and I'm looking at making my first engine after studying a ...

  1. #1
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    Passing a string to a constructor?

    Okay so I'm currently starting to work in SFML and I'm looking at making my first engine after studying a few other game engines I've seen. So basically right now I have a "gamestate" class then another class for levels. I'm trying to pass a string to the other class so I can change what the window title says to get an idea of how things work.. so I will show you an example.

    Code:
    #include <string>
    #include <iostream>
    Class A
    {
         public:
            void function(std::string);
    };
    void A::function(std::string Name)
    {
        std::cout<< Name;
    }
    
    int main()
    {
        A a;
        a.function("string to window");
    }
    I'm getting the following errors:
    Code:
    /home/cody/Documents/GameEngine/src/GameState.cpp||In member function ‘void GameState::Run()’:|
    /home/cody/Documents/GameEngine/src/GameState.cpp|18|error: no matching function for call to ‘Engine::Run(const char [7])’|
    /home/cody/Documents/GameEngine/include/Engine.h|20|note: candidates are: void Engine::Run()|
    ||=== Build finished: 1 errors, 0 warnings ===|
    I see that its trying to pass it is trying to pass it as a character array which obviously wont work, but how do i go about it.. do i need to typecast or something??

    thanks guys,

    Also.. not the appropriate forum but with things like image loading is it necessary to have a class?? I feel simply using functions would be easier. Thanks
    Last edited by codeblue; 04-26-2011 at 10:44 PM.

  2. #2
    -bleh-
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    then overload the constructor with one that take in character array.
    "All that we see or seem
    Is but a dream within a dream." - Poe

  3. #3
    C++ Witch laserlight's Avatar
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    Your example code does not demonstrate the error. (It has a different error due to Class versus class, but after fixing that it compiles perfectly fine.)
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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    Quote Originally Posted by laserlight View Post
    Your example code does not demonstrate the error. (It has a different error due to Class versus class, but after fixing that it compiles perfectly fine.)
    Sorry for basically wasting your time laserlight. I forgot to put std::string in my prototype for the class. My mistake. I didn't event think to check it. Everything is up and working fine now though. Thanks for offering your time.

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    Algorithm Dissector iMalc's Avatar
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    When your car wont start, would you just send a drawing of your car engine to a mechanic?

    I.e. if you want the real problem fixed, show the real code.
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  6. #6
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    Quote Originally Posted by laserlight View Post
    Your example code does not demonstrate the error. (It has a different error due to Class versus class, but after fixing that it compiles perfectly fine.)
    Sorry for basically wasting your time laserlight. I forgot to put std::string in my prototype for the class. My mistake. I didn't event think to check it. Everything is up and working fine now though. Thanks for offering your time.

  7. #7
    a_capitalist_story
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    If you're passing an object to a function and it's not going to be changed, then make it const. Even better, avoid the copy and make it a const reference.

    Code:
    void A::function(const std::string &Name)
    {
        std::cout<< Name;
    }

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