C++のセグメンテーションフォールトを引き起こすテンプレート

Question

以下の単純なコードスニペットでは、デバッガを使用していても私が解読できないという問題があります。あなたの助けを前もってありがとう。

Command.h

class word{ 

    private : static int next_word; 
    private : int word_id; 
    public : word(); 
    public : void grabIt(); 
    public : void raiseIt(); 
    public : void putItDown(); 
}; 
class Command{ 

    public : typedef void(word::*Method)(); 
    private : word* w; 
    private : Method m; 
    public : Command(word *w, Method m); 
    public : void execute(); 
}; 
template<typename T> 
class Queue{ 

    private : enum{ 
    SIZE=9 
    }; 
    private : T* commandArray[SIZE]; 
    private : int m_added = 0, m_removed = 0; 

    public : void enqueue(T* t){ 

     commandArray[m_added] = t; 
     m_added = (m_added + 1) % SIZE; 
    } 
    public : T* dequeue(){ 
     int temp = m_removed; 
     m_removed = (m_removed + 1) % SIZE; 
     return commandArray[temp]; 
    } 
}; 

Command.cpp

int word::next_word = 0; 
word::word(){ 

    this->word_id = next_word++; 
} 
void word::grabIt(){ 
    std::cout << "Grabbed it" << std::endl; 
} 
void word::raiseIt(){ 
    std::cout << "Raised it" << std::endl; 
} 
void word::putItDown(){ 
    std::cout << "Put it down" << std::endl; 
} 
Command::Command(word *w, Method m){ 
    w = w; 
    m = m; 
} 
void Command::execute(){ 
    (w->*m)(); // -------------->>>>> Causing Seg-Fault 
} 

MAIN.CPP

Queue<Command> queue; 
Command *commandArray[9]; 
Command command1(new word, &word::grabIt);  commandArray[0] = &command1; 
Command command2(new word, &word::raiseIt);  commandArray[1] = &command2; 
Command command3(new word, &word::putItDown); commandArray[2] = &command3; 
Command command4(new word, &word::grabIt);  commandArray[3] = &command4; 
Command command5(new word, &word::raiseIt);  commandArray[4] = &command5; 
Command command6(new word, &word::putItDown); commandArray[5] = &command6; 
Command command7(new word, &word::grabIt);  commandArray[6] = &command7; 
Command command8(new word, &word::raiseIt);  commandArray[7] = &command8; 
Command command9(new word, &word::putItDown); commandArray[8] = &command9; 

for(int i=0 ; i < 9; i++){ 
    queue.enqueue(commandArray[i]); 
} 
for(int i=2 ; i < 6 ; i++){ 
    queue.dequeue()->execute(); 
} 

キュー内のいくつかの単語オブジェクトは、デバッガでNULL現れるので、Seg-を引き起こします障害。

Answer 1

、問題を修正する正確な推論について

Command::Command(word *w, Method m) : w(w), m(m){} 

に

Command::Command(word *w, Method m){ 
    w = w; 
    m = m; 
} 

を変更、私は `Command`コンストラクタで、あなたが意図したことをかなり確信しているCan I use identical names for fields and constructor parameters?