why can't compile the code on derived class initialization? - c++

Question

Learning C++ and getting error "no matching function for call to 'Weapon::Weapon(int, const char [4], int, int)'" when creating a weapon istance
Weapon MyWeapon(1,"test",4,1);
Where is the bug?
item.h
#ifndef ITEM_H
#define ITEM_H
#include <string>
#include <iostream>
using namespace std;
class Item
{
public:
string name;
int weight;
int value;
Item(string n, int w, int v);
};
#endif
item.cpp
#include <iostream>
#include <string>
#include <vector>
#include "item.h"
using namespace std;
Item::Item(string name, int weight, int value)
{
name=name;
weight=weight;
name=value;
}
weapon.h
#ifndef WEAPON_H
#define WEAPON_H
#include "item.h"
class Weapon : public Item
{
public:
int damage;
Weapon();
Weapon(int damage);
};
#endif
weapon.cpp
#include <iostream>
#include <string>
#include <vector>
#include "weapon.h"
using namespace std;
Weapon::Weapon( damage): Item(name, weight, value){}

Answer 1

You need to explicitly specify all the Item arguments in the Weapon constructor.
Change the header like this:
Weapon(int damage, string n, int w, int v);
And the implementation like that:
Weapon::Weapon(int damage, string n, int w, int v): damage(damage), Item(name, weight, value){}

Answer 2

You're getting "no matching function for call to Weapon::Weapon(int, const char [4], int, int)" because there isn't a constructor with that signature. Change the Weapon definition to something like this:
class Weapon : public Item
{
public:
int damage;
Weapon(int damage, std::string name, int weight, int value);
};
Then fix up weapon.cpp to send those arguments to the Item constructor:
Weapon::Weapon(int damage, std::string name, int weight, int value) :
Item(name, weight, value),
damage(damage)
{ }
Also a quick side note: using namespace std is considered a bad practice.