fill an array of type class inside another class

Question

I am new in c++ recently i started learning poo I want to create a class movies and a class. directors a class movie should have an array of directors and I want to fill that array from the console. When I run the code it show me the first and second line and stop executing : enter image description here this is my code:

#include<iostream>
#include<string>

using namespace std;

class directors{
   string name;
   string lastname;
       public:
           directors(){
               
           }
           directors(string a,string b){
               name=a;
               lastname=b;
           }
           void createdirector(){
                   cout<<"name of director:"<<endl;
                   cin>>name;
                   cout<<"last name:"<<endl;
                   cin>>lastname;
           }
       
           
};

class movie{
   string name;
   directors* director;
   public:
       film(){
           directors* director=new directors[20];
       };

       void creatmovie(){
           cout<<"name of movie"<<endl;
           cin>>name;
           director[0].createdirector();
       }   
};

int main(){ 
movie a; 
a.creatmovie(); 

}

Use `std::vector`. Anyhow, please extract and provide a [mcve] and the output it produces as text. As a new user her, please also take the [tour] and read [ask]. — Ulrich Eckhardt, Dec 29 '21 at 12:21
Being new to C++, the first thing you should do is get yourself a [good C++ book](https://stackoverflow.com/a/388282/4641116). — Eljay, Dec 29 '21 at 12:26
Your code shouldn't even compile: You've added a `film` member to `movie` that uses the syntax of a constructor, but uses a name different to the name of the containing class. Furthermore any class that dynamically allocates resources should also contain logic to free those resources, usually in a destructor, so assuming you do allocate memory for the array `movie::director`, there should be destructor doing `delete[] director;` For this to work properly you need to make sure that if the constructor completes successfully, `director` either contains a value allocated via `new[]`, or null. — fabian, Dec 29 '21 at 12:33

Jason · Accepted Answer · 2021-12-29T13:02:58.587

A better way wold be to use std::vector as shown below. The advantage of using a std::vector is that you don't have to worry about manual memory management(like using new and delete explicitly). vector will take care of it(memory management). You can use the below given example as a reference.

#include<iostream>
#include<string>
#include <vector>


class director{
   std::string name;
   std::string lastname;
       public:
           director(){
               
           }
           //use constructor initializer list
           director(std::string a,std::string b): name(a), lastname(b){
               
           }
           
           void createDirector() 
           {
                   std::cout<<"Enter name of director:"<<std::endl;
                   std::cin>>name;
                   std::cout<<"Enter last name:"<<std::endl;
                   std::cin>>lastname;
           }
           void displayDirector() const
           {
               std::cout << "Firstname: "<<name<<" Lastname: "<<lastname<<std::endl;
               
           }
       
           
};

class movie{
   std::string name;
   std::vector<director> directors; //vector of director objects
   public:
       
       //constructor that creates vector directors of size vecSize 
       movie(size_t vecSize): directors(vecSize)
       {
           std::cout << "Enter name of movie: "<<std::endl;
           std::cin >> name;
           
           //iterate through the vector and call method createDirector on each element 
           for(director &elem: directors)
           {
               elem.createDirector();
           }
       }
       
       void displayMovie()
       {
           std::cout<<"Movie's name is: "<<name<<std::endl;
           //iterate through the vector and call displayDirector on each object 
           for(const director& elem: directors)
           {
               elem.displayDirector();
           }
           
       }
};

int main(){ 
    movie a(4); //create an object of type movie. Note i have passed 4 as argument you can pass other numbers like 3,2 etc
    a.displayMovie();//display movie info

}

Some of the modifications that i made are:

Used constructor initializer list in class director
added a method called displayDirector in class director
added a method called displayMovei in class movie
added a data member called directors that is a std::vector<director> in class movie.
added a constructor for class movie that initializes the data member directors.
removed unnecessary method namedfilm from class movie
not used using namespace std; which is a recommended practice

The output of the above program can be seen here.

fill an array of type class inside another class

1 Answers1