C++

Forum

 
 
Struggling with Vectors

zxrp (43)
Hey guys, I'm struggling with the functionality of a certain function for a program I'm writing, the specification for the function is as follows:
name(): Should return the string “Drug: ” followed by the drug name and the the names of the components
inside brackets. If one of the components is a drug itself, the entire sub-drug and all its components
should also be added.


I'm struggling with the name() function as I do not yet fully understand the working of Vectors, any help on how to define this function will be greatly appreciated.

Drug.cpp 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
 
#ifndef DRUG_H
#define	DRUG_H

#include "Component.h"
#include <vector>

class Drug : public Component
{
	public:
		Drug(string name);
		virtual ~Drug();
		void administer();
		string name();
		void add(Component *component);
		virtual void mix();
	 
	private:
		vector<Component*> mComponents;
};

#endif


Drug.h 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
 
#include "Drug.h"
 
 Drug::Drug(string name)
       : Component(name)
 {
   
 }
 
 Drug::~Drug()
 {
    vector<Component*>:: iterator it;
    
    for (it = mComponents.begin(); it != mComponents.end(); ++it)
    {
	delete *it;
    }
 }
 
 void Drug::administer()
 {
    cout << "Administering drug ..." << endl;
 }
 
 void Drug::add(Component *component)
 {
    mComponents.push_back(component);
 }
 
//My attempt at defining the name() function, this is incorrect however.
//mName is a protected variable in the parent class.
 string Drug::name()
 {
    string out = "Drug: " + mName + " [ ";
   
    for (int i = 0; i < mComponents.size(); ++i)
    {
	out += mComponents[i] + ", ";
    }
    
    out += " ]";
    
    return out;
 }
 
 void Drug::mix()
 {
    cout << "Mixing drug ..." << name() << endl;
 }
Last edited on
keskiverto (10365)
Please show the definition of Component.
ne555 (10692)
> this is incorrect however
¿in which way?
(compile error, runtime error, wrong output)


You may want virtual string name();
Also, take a look at smart pointers
zxrp (43)
definition of Component:

Component.h 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
 
#ifndef COMPONENT_H
#define	COMPONENT_H

#include <string>
#include <iostream>

using namespace std;

class Component
{

	public:

		Component(string name);
		virtual void add(Component *component);
		virtual string name() = 0;

	protected:

		string mName;

};

#endif


Component.cpp 
1
2
3
4
5
6
7
 
#include "Component.h"

Component::Component(string name)
{
    mName = name;
}


keskiverto (10365)
Aha! The name() is virtual.

The vector has pointers. Pointers to Components. The only thing that we should use is the interface of Component.
1
2
3
4
5
6
7
8
9
10
11
 
string Drug::name()
 {
    string out { "Drug: " };
    out += mName + " [ ";
    for ( auto c : mComponents )
    {
	out += c->name() + ", ";
    }
    out += " ]";
    return out;
 }
MikeyBoy (5631)
Why is Drug.h trying to include itself?
AbstractionAnon (6954)
It's not. The OP reversed the labels for the drug.h and drug.cpp snippets.
zxrp (43)
@keskiverto, thank you so much! That helped a lot.
MikeyBoy (5631)
AbstractionAnon wrote:
It's not. The OP reversed the labels for the drug.h and drug.cpp snippets.

D'oh!
Topic archived. No new replies allowed.