链表，类结构？

Question

Can u build a struct with a class type data member?

I have a class file and my goal is to build a linked lints of characters each with their own names and other attributes.

now to build the list i need a member that will hold the data and a node pointer my question is could i build something like this. all this is being done in a class file and whenever i run it i get an error at the struct, BigHero doesn't name type.

help this noob XD

 #include <string>
 #include <iostream>

 using namespace std;

 #ifndef BIGHERO_H
 #define BIGHERO_H

struct Node{
    BigHero data;
    Node* Next;
    };

class BigHero
{
 public:

     BigHero();

     /* Parameterized constructor
      * Set private members to parameter values
      * NOTE:  level is initialized as the interger division of exp/100
      *        i.e. if exp = 250 -> level = 2       */
       BigHero(string newName, int newExp, int newStr, int newIntel, int            newDex);

        /* Accessors:  each accessor will return the value of the appropriate 
        private data member */
        string getName() const;
        int getExp() const;
        int getStr() const;
        int getInt() const;
        int getDex() const;
        int getLevel() const;

        /* Mutators:  each mutator will take one parameter and update the    

         appropriate private data member 
        * The domain for each mutator is listed below.  
        * The mutator should protect against invalid values.  
        * An Invalid entry should result in the original value remaining unchanged. */
         void setName( string newName );   // All strings are valid
         void setExp( int newExp );        // 0 <= newExp <= 9000
         void setStr( int newStr );        // 0 <= newStr <= 300
         void setInt( int newInt );        // 0 <= newInt <= 300
         void setDex( int newDex );        // 0 <= newDex <= 300
         void setLevel( int newLevel );    // 1 <= newLevel <= 100


         bool addExp( int amount );


         void levelUp();

        bool operator<( const BigHero& rhs ) const;
        bool operator>( const BigHero& rhs ) const;
        bool operator==( const BigHero& rhs ) const;


       friend ostream& operator<< (ostream& os, const BigHero& rhs);

     /* Input should be in the format: "Name exp Str Intel Dex" 
     * Don't forget to update level value to be equal to the integer division of exp/100 */
       friend istream& operator>> (istream& is, BigHero& rhs);

     ~BigHero();

     private:
         string name;    // Hero's name
         int exp;        // Experience points (100 exp = 1 level)
         int level;      // Hero's level
         int Str;        // Hero's strength
         int Intel;      // Hero's intelligence
         int Dex;        // Hero's dexterity

         Node* head;
         Node* tail;


        };

        #endif // BIGHERO_H

Answer 1

Node contains a BigHero , so to allocate a Node , Node needs to know the size of BigHero to be able to determine how much storage is required. That means BigHero must be fully defined, and it's size known, before Node can be defined.

class BigHero
{
     // Rest of BigHero omitted to save space
     Node* head;
     Node* tail;
};

struct Node{
    BigHero data;
    Node* Next;
};

But...

BigHero needs to know that the concept of Node exists and will be defined elsewhere to be able to contain pointers to Node . This is solved with a forward definition of Node . So

struct Node;
class BigHero
{
     // Rest of BigHero omitted to save space
     Node* head;
     Node* tail;
};

struct Node{
    BigHero data;
    Node* Next;
};

Answer 2

I suspect the problem is that the C++ compiler hasn't seen the BigHero class yet when it gets to the struct definition, so it doesn't know what to do with it.

Forward-declare the BigHero class by putting this:

class BigHero;

Before the Node struct.