I don't get this

This is a discussion on I don't get this within the C++ Programming forums, part of the General Programming Boards category; Code: #include "Project1App.h" #include "Project1Frm.h" #include <string> string n; IMPLEMENT_APP(Project1FrmApp) bool Project1FrmApp::OnInit() { Project1Frm* frame = new Project1Frm(NULL); SetTopWindow(frame); frame->Show(); ...

  1. #1
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    Aug 2007
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    I don't get this

    Code:
    #include "Project1App.h"
    #include "Project1Frm.h"
    #include <string>
    string n;
    
    IMPLEMENT_APP(Project1FrmApp)
    
    
    bool Project1FrmApp::OnInit()
    {
        Project1Frm* frame = new Project1Frm(NULL);
        SetTopWindow(frame);
        frame->Show();
        return true;
    }
    
    int Project1FrmApp::OnExit()
    {
    	return 0;
    }
    Error: 15 C:\wxdevcpp\proiecte\1st\Project1App.cpp `string' does not name a type

    I'm trying to declare a vector visible outside the wx implementation, but that did not work, so i cam back to an int. It worked, char worked, but string and any other standard class, doesn't. This is so annoying. I almost thought I got the smallest hang of C++.

  2. #2
    Registered User hk_mp5kpdw's Avatar
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    Maybe std::string?
    "Owners of dogs will have noticed that, if you provide them with food and water and shelter and affection, they will think you are god. Whereas owners of cats are compelled to realize that, if you provide them with food and water and shelter and affection, they draw the conclusion that they are gods."
    -Christopher Hitchens

  3. #3
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    oh. what's std, and what does :: do?

  4. #4
    Registered User MacNilly's Avatar
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    std is a namespace, which is particular to C++ and not in the C language.

    Namespaces are essentially a way to group data and functions under a unique name. This gets rid of the problem of having name collisions which are a compiler error. the std namespace incorportates functions and data from the Standard Template Library (STL). The :: operator is called the scope-resolution operator and explicity tells the compiler what class or namespace you want to use.

  5. #5
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    Instead of writing out "std::string" everytime, consider adding a line "using std::string;" at the top. Some people use "using namespace std;" to import the whole namespace, but many others don't like that idea.

  6. #6
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    Hmm, sounds like a pretty smart addition to the basic C. I'll have to experiment with it. Thanks!

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