在C ++中用对象填充列表时出现奇怪的问题? [英] Bizarre issue when populating a list with objects in C++?

问题描述

我创建了一个类Patient，我想用通过显式构造函数创建的对象填充Patients列表.但是，当我尝试使用`= {}(初始化列表)填充list<Patient>时，出现错误Type name is not allowed.我想问我在做什么错了吗?

I have created a class Patient and I want to populate a list of Patients with objects which I have created via the explicit constrctor. However I get an error Type name is not allowed when I try to populate the list<Patient> using the `={}(initializer list). I would like to ask what am I doing wrong?

#include "pch.h"
#include <iostream>
#include <string>
#include <list>
using namespace std;
class Patient {
    string name;
    string birthday;
    int visits;
    public:
    Patient(string n, string b, int v) {
        name = n;
        birthday = b;
        visits = v;
    }

};
list<Patient> sp = {
Patient a("I.Petrov", "21.12.02", 4),
Patient b("D.Stoyanov", "12.02.97", 7),
Patient c("K.Dimitrov", "07.08.90", 1)
};

int main()
{



    return 0;
}

推荐答案

列表的初始化程序采用一系列表达式，但是您给了它完整的变量声明.那根本就是无效的语法.您只能在函数或命名空间范围内的自由空间"中放置声明，而不能在其他语句中放置声明(出于此答案的目的，我们将忽略条件语句的乐趣).

The list's initializer takes a sequence of expressions, but you've given it full variable declarations instead. That's simply not valid syntax. You can only put declarations in "free space" in a function or at namespace scope, not inside another statement (we'll ignore the joys of conditionals for the purpose of this answer).

您可能打算创建一些临时对象:

You probably intended to create some temporaries instead:

list<Patient> sp = {
   Patient("I.Petrov", "21.12.02", 4),
   Patient("D.Stoyanov", "12.02.97", 7),
   Patient("K.Dimitrov", "07.08.90", 1)
};

但是我将其写为:

std::list<Patient> sp{
   {"I.Petrov",   "21.12.02", 4},
   {"D.Stoyanov", "12.02.97", 7},
   {"K.Dimitrov", "07.08.90", 1}
};

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