Question

所以我有以下问题。我有一个是另外两个类的子类的类，它们两个都有位置。像本例一样：

struct A
{
    float x, y;
    std::string name;

    void move(float x, float y)
    {
        this->x += x;
        this->y += y;
    }
};

struct B
{
    float x, y;
    int rows, columns;

    void move(float x, float y)
    {
        this->x += x;
        this->y += y;
    }
};

struct C : public A, public B
{
    void move(float x, float y)
    {
        this->x += x; //generates error: "C::x is ambiguous
        this->y += y; //generates error: "C::y is ambiguous
    }
};

稍后在代码中，我将C类称为A类和B类，当我获得职位时，我遇到了问题。我可以以某种方式“组合”两个类的位置变量吗？如果不能，那么我可以同时更改两个班级的职位，还是必须这样做：

void move(float x, float y)
{
    this->x1 += x;
    this->y2 += y;
    this->x1 += x;
    this->y2 += y;  
}

谢谢！

Answer 1

在C ++中，可以通过在成员变量的类范围前添加前缀来消除歧义：

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var config = require('./config.js');
var nforce = require('nforce');
var dateTime = require('node-datetime');

var routes = require('./routes/index');

var app = express();
var server = require('http').Server(app);
var dt = dateTime.create();

var io = require('socket.io')(server);
// get a reference to the socket once a client connects
var socket = io.sockets.on('connection', function (socket) { });

var org = nforce.createConnection({
  clientId: config.CLIENT_ID,
  clientSecret: config.CLIENT_SECRET,
  redirectUri: config.CALLBACK_URL + '/oauth/_callback',
  mode: 'multi',
  environment: config.ENVIRONMENT,  // optional, sandbox or production, production default
    apiVersion: 'v43.0'
});

org.authenticate({ username: config.USERNAME, password: config.PASSWORD }, function(err, oauth) {

  if(err) return console.log(err);
  if(!err) {
    console.log('*** Successfully connected to Salesforce ***');
    // add any logic to perform after login
  }

  // subscribe to a pushtopic
  var str = org.stream({ topic: config.PUSH_TOPIC, oauth: oauth });

  str.on('connect', function(){
    console.log('Connected to pushtopic: ' + config.PUSH_TOPIC);
  });

  str.on('error', function(error) {
    console.log('Error received from pushtopic: ' + error);
  });

  str.on('data', function(data) {
    console.log('Received the following from pushtopic ---');
    console.log(data);
    var dataStream1 = data['sobject'];
    dataStream1['timestamp'] = dateTime.create().format('Y-m-d H:M:S');
    var dataStreamFinal = '[' + JSON.stringify(dataStream1) + ']';

    var kafka = require('kafka-node'),
        HighLevelProducer = kafka.HighLevelProducer,
        client = new kafka.Client(),
        producer = new HighLevelProducer(client),
        payloads = [
        { topic: 'testing1', messages: dataStreamFinal}
    ];

    producer.on('ready', function () {
        producer.send(payloads, function (err, data) {
        console.log(data);
    });
});

    // emit the record to be displayed on the page

//Send to kafka topic
    socket.emit('record-processed', JSON.stringify(dataStreamFinal));
  });

});

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'hbs');

app.use(function(req, res, next){
  res.io = io;
  next();
});

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', routes);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});


module.exports = {app: app, server: server};

如何解决多次继承的模棱两可的变量名称？

1 个答案: