I created a class called "Message". I want to store Messages that are created with the class "Message" in a static vector array in a class named "MessageBox". The compiler tells me that Message doesn't exist, but the editor is telling me otherwise. Here are the files with the code:
"Message.h"
#pragma once
#include <iostream>
#include <string>
#include "Message Box.h"
namespace ATE {
class Message
{
public:
Message(std::string act, std::string ID, std::string IDtwo) { action = act, ID1 = ID, ID2 = IDtwo; }
Message(std::string act, std::string ID) { action = act, ID1 = ID; }
std::string action;
std::string ID1;
std::string ID2 = nullptr;
};
}
"Message Box.h"
#pragma once
#include <string>
#include <vector>
#include "Message.h"
namespace ATE {
class MessageBox
{
public:
static std::vector<Message> MsgBox;
void addMessage(Message msg);
};
}
"Message Box.cpp"
#include "Message Box.h"
void ATE::MessageBox::addMessage(Message msg)
{
MsgBox.push_back(msg);
}
My errors:
Error C2065 'Message': undeclared identifier (file: message box.h, line: 11)
Error C2923 'std::vector': 'Message' is not a valid template type argument for parameter '_Ty' (file: message box.h, line: 11)
Error C2061 syntax error: identifier 'Message' (file: message box.h, line: 12)
Help is much appreciated (:
Your headers include each other. Due to the #pragma once
if you include Message.h
first in some .cpp file the compiler will see Message Box.h
's content "inside" Message.h
- exactly at the #include "Message Box.h"
line. As result the compiler will process your source code in the following order:
source.cpp:
//#include "Message.h"
message.h:
//#pragma once
//#include <iostream>
iostream:
//iostream's content
message.h(resumed):
//#include <string>
string:
//string's content
message.h(resumed):
#include "Message Box.h"
Message Box.h:
#pragma once
#include <string>
// string's content already included, won't include again
#include <vector>
// vector's content
#include "Message.h"
// message.h won't include again, due to the #pragma once
namespace ATE {
class MessageBox
{
public:
static std::vector<Message> MsgBox;
At this point the name Message
is used, but the compiler has not reached it's definition in Message.h
yet and gives you an error.
Removing the #pragma once
won't help. You need to remove the circular dependency. In this case remove the #include "Message Box.h"
from Message.h
and you'll be fine.
In "Message.h", remove the:
#include "Message Box.h"
It add the Message Box
declaration before the Message
.
In "Message Box.cpp" Add this line after the includes:
std::vector<ATE::Message> ATE::MessageBox::MsgBox;
A static
member must be declared again outside.
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