小编Mik*_*ike的帖子

我创建了一个简单的电报机器人：

import logging
from telegram.ext import Updater, CommandHandler, MessageHandler, Filters
import os
PORT = int(os.environ.get('PORT', 8443))

# Enable logging
logging.basicConfig(format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
                    level=logging.INFO)

logger = logging.getLogger(__name__)
TOKEN = 'YOURTELEGRAMBOTTOKEN'

# Define a few command handlers. These usually take the two arguments update and
# context. Error handlers also receive the raised TelegramError object in error.
def start(update, context):
    """Send a message when the command /start is issued."""
    update.message.reply_text('Hi!')

def help(update, context):
    """Send a message when the …

我对 C++ 很陌生。我编写了一个函数模板来对向量中的所有元素求和，如下所示：

template<typename T>
inline T sumator(const std::vector<T> &sequence) {
    T init = T{};
    return accumulate(sequence.begin(), sequence.end(), init);
}

一切正常，直到默认构造函数没有声明，而是从例如 2 个参数声明构造函数。像这样：

class A {
    private:
        int a;
        int b;
    public:
//        A() = default;
        A(int aa, int bb) : a(aa),b(bb){};
        A operator+(const A &right) const {
            return {a + right.a, b + right.b};
        }
        bool operator==(const A &right) const {
            return (a == right.a && b == right.b);
        }

    };
    vector<A> bc = {{3,5},{5,5}};
    A res = Adder::sumator(works); …