Question

so ive been tryind to create a simple array list class and got stuck allready in the beginning…

my header file ( i deleted my .cpp file and still got the same message )

#ifndef ARRAYLIST_H
#define ARRAYLIST_H

#include <iostream>
using namespace std;

template <typename T>

class ArrayList {
private:
    T *arr;
    int length;

public:
    ArrayList();

    void Insert(T item);

    void Print();

    //friend &ostream operator<< (ostream &out, ArrayList &al);
};

#endif

and my error

1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall ArrayList<int>::ArrayList<int>(void)" (??0?$ArrayList@H@@QAE@XZ) referenced in function _main
1>C:\Users\Gannash\Desktop\Programming\C++WS\XMLReader\Debug\XMLReader.exe : fatal error LNK1120: 1 unresolved externals

Answer 1

It is like you only declared methods of the class and not defined them

Put all the definitions in the header