c++ - 使用未声明的标识符 c++ xcode

Question

我在cocos2d-x工作，求助这个问题。此行错误

string route = pathFind(xA, yA, xB, yB);

代码 HelloWorldScene.cpp

#include "HelloWorldScene.h"
#include "SimpleAudioEngine.h"
#include <iostream>
#include <iomanip>
#include <math.h>
#include <queue>
#include <string>
using namespace std;
using namespace cocos2d;
using namespace CocosDenshion;


const int n = 20; // horizontal size of the map
const int m = 20; // vertical size size of the map
static int MAPP[n][m];
static int putX[100];
static int putY[100];
static int closed_nodes_map[n][m]; // map of closed (tried-out) nodes
static int open_nodes_map[n][m]; // map of open (not-yet-tried) nodes
static int dir_map[n][m]; // map of directions
const int dir = 8; // number of possible directions to go at any position
static int dx[dir] = { 1, 1, 0, -1, -1, -1, 0, 1 };
static int dy[dir] = { 0, 1, 1, 1, 0, -1, -1, -1 };

class node
{
    // current position
    int xPos;
    int yPos;
    // total distance already travelled to reach the node
    int level;
    // priority=level+remaining distance estimate
    int priority;  // smaller: higher priority


public:
    node(int xp, int yp, int d, int p)
    {
        xPos = xp; yPos = yp; level = d; priority = p;
    }

    int getxPos() const { return xPos; }
    int getyPos() const { return yPos; }
    int getLevel() const { return level; }
    int getPriority() const { return priority; }

    void updatePriority(const int & xDest, const int & yDest)
    {
        priority = level + estimate(xDest, yDest) * 10; //A*
    }

    // give better priority to going strait instead of diagonally
    void nextLevel(const int & i) // i: direction
    {
        level += (dir == 8 ? (i % 2 == 0 ? 10 : 14) : 10);
    }

    // Estimation function for the remaining distance to the goal.
    const int & estimate(const int & xDest, const int & yDest) const
    {
        static int xd, yd, d;
        xd = xDest - xPos;
        yd = yDest - yPos;

        // Euclidian Distance
        d = static_cast<int>(sqrt(xd*xd + yd*yd));

        // Manhattan distance
        //d=abs(xd)+abs(yd);

        // Chebyshev distance
        //d=max(abs(xd), abs(yd));

        return(d);
    }
};



CCScene* HelloWorld::scene()
{
    // 'scene' is an autorelease object
    CCScene *scene = CCScene::create();

    // 'layer' is an autorelease object
    HelloWorld *layer = HelloWorld::create();

    // add layer as a child to scene
    scene->addChild(layer);

    // return the scene
    return scene;
}

// on "init" you need to initialize your instance
bool HelloWorld::init()
{
    //////////////////////////////
    // 1. super init first
    if ( !CCLayer::init() )
    {
        return false;
    }

    for (int y = 0; y < m; y++)
    {
        for (int x = 0; x < n; x++) MAPP[x][y] = 0;
    }

    int xA=0, yA=0, xB=7, yB=5;
    // get the route
    string route = pathFind(xA, yA, xB, yB);
    // follow the route on the map and display it
    if (route.length() > 0)
    {
        int j; char c;
        int x = xA;
        int y = yA;
        MAPP[x][y] = 2;
        for (int i = 0; i < route.length(); i++)
        {
            c = route.at(i);
            j = atoi(&c);
            x = x + dx[j];
            y = y + dy[j];
            MAPP[x][y] = 3;
        }
        MAPP[x][y] = 4;
    }


    int putS=0;
    for (int y = 0; y < m; y++)
    {
        for (int x = 0; x < n; x++)
        {
            if (MAPP[x][y] == 3)
            {
                putY[putS] = y;
                putX[putS] = x;
                putS++;
            }
        }
    }

    return true;
}

bool operator < (const node & a, const node & b)
{
    return a.getPriority() > b.getPriority();
}

// A-star algorithm.
// The route returned is a string of direction digits.
string pathFind(const int & xStart, const int & yStart,
                const int & xFinish, const int & yFinish)
{
    static priority_queue<node> pq[2]; // list of open (not-yet-tried) nodes
    static int pqi; // pq index
    static node* n0;
    static node* m0;
    static int i, j, x, y, xdx, ydy;
    static char c;
    pqi = 0;

    // reset the node maps
    for (y = 0; y < m; y++)
    {
        for (x = 0; x < n; x++)
        {
            closed_nodes_map[x][y] = 0;
            open_nodes_map[x][y] = 0;
        }
    }

    // create the start node and push into list of open nodes
    n0 = new node(xStart, yStart, 0, 0);
    n0->updatePriority(xFinish, yFinish);
    pq[pqi].push(*n0);
    open_nodes_map[x][y] = n0->getPriority(); // mark it on the open nodes map

    // A* search
    while (!pq[pqi].empty())
    {
        // get the current node w/ the highest priority
        // from the list of open nodes
        n0 = new node(pq[pqi].top().getxPos(), pq[pqi].top().getyPos(),
                      pq[pqi].top().getLevel(), pq[pqi].top().getPriority());

        x = n0->getxPos(); y = n0->getyPos();

        pq[pqi].pop(); // remove the node from the open list
        open_nodes_map[x][y] = 0;
        // mark it on the closed nodes map
        closed_nodes_map[x][y] = 1;

        // quit searching when the goal state is reached
        //if((*n0).estimate(xFinish, yFinish) == 0)
        if (x == xFinish && y == yFinish)
        {
            // generate the path from finish to start
            // by following the directions
            string path = "";
            while (!(x == xStart && y == yStart))
            {
                j = dir_map[x][y];
                c = '0' + (j + dir / 2)%dir;
                path = c + path;
                x += dx[j];
                y += dy[j];
            }

            // garbage collection
            delete n0;
            // empty the leftover nodes
            while (!pq[pqi].empty()) pq[pqi].pop();
            return path;
        }

        // generate moves (child nodes) in all possible directions
        for (i = 0; i < dir; i++)
        {
            xdx = x + dx[i]; ydy = y + dy[i];

            if (!(xdx<0 || xdx>n - 1 || ydy<0 || ydy>m - 1 || MAPP[xdx][ydy] == 1
                  || closed_nodes_map[xdx][ydy] == 1))
            {
                // generate a child node
                m0 = new node(xdx, ydy, n0->getLevel(),
                              n0->getPriority());
                m0->nextLevel(i);
                m0->updatePriority(xFinish, yFinish);

                // if it is not in the open list then add into that
                if (open_nodes_map[xdx][ydy] == 0)
                {
                    open_nodes_map[xdx][ydy] = m0->getPriority();
                    pq[pqi].push(*m0);
                    // mark its parent node direction
                    dir_map[xdx][ydy] = (i + dir / 2)%dir;
                }
                else if (open_nodes_map[xdx][ydy] > m0->getPriority())
                {
                    // update the priority info
                    open_nodes_map[xdx][ydy] = m0->getPriority();
                    // update the parent direction info
                    dir_map[xdx][ydy] = (i + dir / 2)%dir;

                    // replace the node
                    // by emptying one pq to the other one
                    // except the node to be replaced will be ignored
                    // and the new node will be pushed in instead
                    while (!(pq[pqi].top().getxPos() == xdx &&
                             pq[pqi].top().getyPos() == ydy))
                    {
                        pq[1 - pqi].push(pq[pqi].top());
                        pq[pqi].pop();
                    }
                    pq[pqi].pop(); // remove the wanted node

                    // empty the larger size pq to the smaller one
                    if (pq[pqi].size() > pq[1 - pqi].size()) pqi = 1 - pqi;
                    while (!pq[pqi].empty())
                    {
                        pq[1 - pqi].push(pq[pqi].top());
                        pq[pqi].pop();
                    }
                    pqi = 1 - pqi;
                    pq[pqi].push(*m0); // add the better node instead
                }
                else delete m0; // garbage collection
            }
        }
        delete n0; // garbage collection
    }
    return ""; // no route found
}


void HelloWorld::menuCloseCallback(CCObject* pSender)
{
    CCDirector::sharedDirector()->end();

#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
    exit(0);
#endif
}

代码HelloWorldScene.h

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h"

class HelloWorld : public cocos2d::CCLayer
{
public:
    // Method 'init' in cocos2d-x returns bool, instead of 'id' in cocos2d-iphone (an object pointer)
    virtual bool init();

    // there's no 'id' in cpp, so we recommend to return the class instance pointer
    static cocos2d::CCScene* scene();

    // a selector callback
    void menuCloseCallback(CCObject* pSender);

    // preprocessor macro for "static create()" constructor ( node() deprecated )
    CREATE_FUNC(HelloWorld);

};



#endif // __HELLOWORLD_SCENE_H__

Answer 1

pathFind 是一个函数，您应该为它制作原型(prototype)。将其添加到 HelloWorldScene.cpp 顶部的某处

string pathFind(const int & xStart, const int & yStart,
                const int & xFinish, const int & yFinish);

或者，如果您打算从另一个模块调用此函数，则将原型(prototype)放在适当的头文件中。