Hello all,
I have the simplest code that I want to separate in three files:
- Header file: class and struct declarations. No implementations at all.
- Inline functions file: implementation of inline methods in header.
- Code file: normal C++ code for more complicated implementations.
When I was about to implement an operator[] method, I couldn't manage to compile it. Here is a minimal example that shows the same problem:
Header (myclass.h):
#ifndef _MYCLASS_H_
#define _MYCLASS_H_
class MyClass
{
public:
MyClass(const int n);
virtual ~MyClass();
double& operator[](const int i);
double operator[](const int i) const;
void someBigMethod();
private:
double* arr;
};
#endif /* _MYCLASS_H_ */
Inline functions (myclass-inl.h):
#include "myclass.h"
inline double& MyClass::operator[](const int i) {
return arr[i];
}
inline double MyClass::operator[](const int i) const {
return arr[i];
}
Code (myclass.cpp):
#include "myclass.h"
#include "myclass-inl.h"
#include <iostream>
inline MyClass::MyClass(const int n) {
arr = new double[n];
}
inline MyClass::~MyClass() {
delete[] arr;
}
void MyClass::someBigMethod() {
std::cout << "Hello big method that is not inlined" << std::endl;
}
And finally, a main to test it all:
#include "myclass.h"
#include <iostream>
using namespace std;
int main(int argc, char *argv[]) {
MyClass m(123);
double x = m[1];
m[1] = 1234;
cout << "m[1]=" << m[1] << endl;
x = x + 1;
return 0;
}
void nothing() {
cout << "hello world" << endl;
}
When I compile it, it says:
main.cpp:(.text+0x1b): undefined reference to 'MyClass::MyClass(int)'
main.cpp:(.text+0x2f): undefined reference to 'MyClass::operator[](int)'
main.cpp:(.text+0x49): undefined reference to 'MyClass::operator[](int)'
main.cpp:(.text+0x65): undefined reference to 'MyClass::operator[](int)'
However, when I move the main method to the MyClass.cpp file, it works. Could you guys help me spot the problem?
Thank you.