C++代碼，只讀變量不可賦值

這裏是C++代碼。我很困惑，爲什麼解引用迭代器告訴我變量是隻讀的？它是Node類的公共成員。我的錯誤是什麼？C++代碼，只讀變量不可賦值

adjTable是一組節點的元素 - 見以下聲明的。

Cells::iterator pos = adjTable.find(*thisNode); 
if (pos == adjTable.end()) { // Did we find it? 
    NSLog(@"Not found"); 
// What to do here if node not found 
} 
// We found the node - mark it as grey in the table 
(*pos).colour = grey; // <<<<<<<< this is the line with the issue

這裏是聲明等。（它似乎沒有以正確格式）

class Node { // Define a single node a.k.a. matrix cell 
public: 
    short nodeID;   // the tag from the cell 
    short colour;   // for tri-colour used in traversing 
    std::vector<short>adjs; // nodeIDs of adjacent nodes 

    // Ctors 
    Node(){}; 
    Node(short ID, short col, std::vector<short>adjs) 
     : nodeID(ID), colour(col), adjs(adjs){} 
    // Dtors 
    ~Node(){}; 
    // operators 
    bool operator<(const Node& rhs) const{ 
     return nodeID < rhs.nodeID; 
    } 
    bool operator==(const Node& rhs) const{ 
     return nodeID == rhs.nodeID; 
    } 
}; 

typedef std::set<Node,SortNodeSet> Cells; 
class MakeTable { 
public: 
    MakeTable(){}; 
    ~MakeTable(){}; 
    Cells makeTable(); 
};

來源

2014-02-09 pteeson

有關'std :: set'修改的其他SO信息http://stackoverflow.com/questions/908949/what-happens-when-you-modify-an-element-of-an-stdset – txtechhelp

此鏈接幫助我。我選擇使用const_cast （（* pos）.colour）= gray; – pteeson