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Multiple definition error using Dev-C++

D3CIM8OR (14)
Hello, I am attempting to code a stack structure in C++ using the Dev-C++ compiler. I currently have 3 files: main.cpp, DataStructures.h, and DataStructures.cpp. Every time I attempt to compile it, I get this error: DataStructures.cpp:(.bss+0x0): multiple definition of `node'. I have looked online and tried using extern, adding header guards, editing the makefile, etc. to no avail.

main.cpp
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#include <iostream>
#include "DataStructures.h"

using namespace std;

int main() {
	Stack theStack;
	cout << theStack.myNode->val;
	return 0;
}


DataStructures.h
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#ifndef DATASTRUCTURES_H
#define DATASTRUCTURES_H

using namespace std;

struct Node {
	int val;
	Node* next;
} node;
typedef Node* nodeptr;

class Stack {
	public:
		Stack();
		~Stack();
		Node* myNode;
	private:
		
};
#endif


DataStructures.cpp
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#include <iostream>
#include "DataStructures.h"

using namespace std;

Stack::Stack() {
	myNode = new Node;
	myNode->val = 10;
	myNode->next = NULL;
}

Stack::~Stack() {
	delete myNode;
}


Makefile.win
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*constants*
*all command*
*clean command*
DataStructures/main.o: DataStructures/main.cpp
	$(CPP) -c DataStructures/main.cpp -o DataStructures/main.o $(CXXFLAGS)

DataStructures/DataStructures.o: DataStructures/DataStructures.cpp
	$(CPP) -c DataStructures/DataStructures.cpp -o DataStructures/DataStructures.o $(CXXFLAGS)

[/code]
ne555 (10692)
http://www.cplusplus.com/forum/general/140198/ (see global variables)
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#ifndef DATASTRUCTURES_H
#define DATASTRUCTURES_H

using namespace std; //don't using on headers, all that includes it will have it.

struct Node {
	int val;
	Node* next;
} node; //<-- here


¿do you really want `node' to be a global variable? you don't even use it.
D3CIM8OR (14)
Ok I've fixed it like you said but it's still giving me the same error
MikeyBoy (5631)
Did you fix both the issues ne555 pointed out?
heepoo (120)
in your linker parameters, write the following command-line parameter:
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-Wl,--allow-multiple-definition
-Wl,--enable-runtime-pseudo-reloc
D3CIM8OR (14)
thank you heepoo it worked. But is it bad that there exists a multiple definition at all?
Last edited on
heepoo (120)
no, the linker resolve's everything itself
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