Question

我正在用c ++实现A *路径查找。我面临的问题与用于结构的指针和引用有关。

在退出for循环后，它遍历openList（向量）并将currentNode设置为具有最小F值的元素，F的类型为int。

当currentNode发生变化时，currentNode分配的for循环中较早的 parent 会被更改

NavigationNode currentNode;

currentNode.x = 1;
currentNode.y = 2;

parent = &currentNode

如果我将currentNode更新为另一个值

currentNode.x =23;
currentNode.y = 1;

父母也会改变。我知道父节点正在保存currentNode的地址。所以任何变化都会得到反映但我想知道如何让父值不被改变。如果我以后更新currentNode

我有一个声明为

的结构

struct NavigationNode{
    int x, y; 
    float f, g, h;
    int value;
    NavigationNode *parent;
};

我创建了一个NavigationNode的startNode

NavigationNode startNode;
startNode.x = START_X;
startNode.y = START_Y;
startNode.g = 0;
startNode.f = 0;

我将其插入名为openList

的矢量中

vector<NavigationNode> openList;
openList.push_back(startNode);

NavigationNode currentNode;

然后我开始寻找路径

while (!openList.empty())
{       
    for (auto i = openList.begin(); i != openList.end(); ++i)
    {
        if (i == openList.begin() || (*i).f <= currentNode.f)
        {
            currentNode = (*i);
        }
    }

    for (int i = 0; i < 8; i++)
    {
         NavigationNode nextNode;
         nextNode.x = xChange;
         nextNode.y = yChange;

         // some logic operations
         // assign the currentNode to the parentNode 

         nextNode.parent = &currentNode;
         nextNode.value = map[xChange][yChange];

         openList.push_back(nextNode);
     }
}

Answer 1

currentNode更改反映在父级中的原因是因为我将地址分配给父级。所以任何变化都会得到反映但是，现在我创建currentNode，作为指针，它将具有不同的地址。并且已经将其余部分声明为指针

   NavigationNode *startNode;
   startNode->x = START_X;
   startNode->y = START_Y;
   startNode->g = 0;
   startNode->f = 0;


   vector<NavigationNode*> openList;
   openList.push_back(*startNode);

    NavigationNode *currentNode = new NavigationNode;



     while (!openList.empty())
     {

    // sort the vector by increasing F values, so the lowest F values will be at the first location
    //  sort(openList.begin(), openList.end(), compareByF);
         for (auto i = openList.begin(); i != openList.end(); ++i){

             if (i == openList.begin() || (*i)->f <= currentNode->f){
               currentNode = (*i);
             }
         }

           for (int i = 0; i < numberOfDirections; i++)
            {
                NavigationNode *nextNode = new NavigationNode;
                nextNode->x = xChange;
                nextNode->y = yChange;

                // some logic operations
                // assign the currentNode to the parentNode 

               nextNode->parent = currentNode;
               nextNode->value = map[xChange][yChange];

               openList.push_back(nextNode);

             } // end for loop

       }// end while loop

c ++结构指针引用值被更改

1 个答案: