Having trouble with constructors which accepts different parameters - c++

Question

I am new to C++ and I am having trouble with class and header files. I am trying to create a constructor to accept various pokemon stats such as strings and integers. I used to code in java and constructors were fairly simple to assign.
Pokemons.h
#ifndef POKEMONS_H
#define POKEMONS_H
#include <string>
#include <iostream>
using namespace std;
class Pokemons {
public:
Pokemons();
};
#endif /* POKEMONS_H */
Pokemons.cpp
#include "Pokemons.h"
#include <string>
using namespace std;
string pokemonName;
string pokemonType1;
string pokemonType2;
int pokemonHP;
int pokemonAttack;
int pokemonDefence;
int pokemonSPAttack;
int pokemonSPDefence;
int pokemonSpeed;
Pokemons::Pokemons(string nm, string tp1, string tp2, int hp, int atk,
int def, int satk, int sdef, int spd) {
pokemonName = nm;
pokemonType1 = tp1;
pokemonType2 = tp2;
pokemonHP = hp;
pokemonAttack = atk;
pokemonDefence = def;
pokemonSPAttack = satk;
pokemonSPDefence = sdef;
pokemonSpeed = spd;
}
main.cpp
#include <iostream>
#include "Pokemons.h"
int main(){
Pokemons p001;
p001.Pokemons("Bulbasaur", "Grass", "None", 31,23,45,43,45,12);
return 0;
}
I am getting the following errors :
Pokemons.cpp:32:9: error: prototype for 'Pokemons::Pokemons(std::string, std::string, std::string, int, int, int, int, int, int)' does not match any in class 'Pokemons'
Pokemons::Pokemons(string nm, string tp1, string tp2, int hp, int atk, int def, int satk, int sdef, int spd) {
In file included from Pokemons.cpp:14:0:
Pokemons.h:21:7: error: candidates are: constexpr Pokemons::Pokemons(Pokemons&&)
class Pokemons {
Pokemons.h:21:7: error: constexpr Pokemons::Pokemons(const Pokemons&)
Pokemons.cpp:30:9: error: Pokemons::Pokemons()
Pokemons::Pokemons(){}

Answer 1

There are three problems here. First, your constructor is declared as Pokemons();, taking zero arguments, but you have a constructor defined as taking many arguments, and so their signatures don't match, and ultimately, because of function overloading in C++, they refer to different functions. Try declaring the constructor as follows in your header file:
class Pokemons {
public:
Pokemons(string nm, string tp1, string tp2, int hp, int atk,
int def, int satk, int sdef, int spd);
};
Now both the definition and declaration should refer to the same function.
The second problem is here:
Pokemons p001;
This implicitly calls the constructor with no arguments. It's important to understand that many functions get called in C++ even though they haven't been explicitly named. To fix this, you should initialize p001 as follows:
Pokemons p001("Bulbasaur", "Grass", "None", 31,23,45,43,45,12);
You should also remove p001.Pokemons("Bulbasaur", "Grass", "None", 31,23,45,43,45,12); on the following line. Now, the compiler can match this call to your constructor taking many arguments.
The third problem for now is that pokemonName all the way through pokemonSpeed are defined outside the Pokemons class, in global scope. This has a similar effect to making a member static in Java. These should be placed inside your class definition, to make them instance members:
class Pokemons {
public:
Pokemons(string nm, string tp1, string tp2, int hp, int atk,
int def, int satk, int sdef, int spd);
private:
string pokemonName;
string pokemonType1;
string pokemonType2;
int pokemonHP;
int pokemonAttack;
int pokemonDefence;
int pokemonSPAttack;
int pokemonSPDefence;
int pokemonSpeed;
};