如何根据C ++中文件的输入为枚举分配一个值？ [英] How to assign a value to an enum based on input from a file in C++?

问题描述

我有一个文件，其值包括：START和STOP。我也有以下枚举：

I have a file with values like: START and STOP. I also have the following enum declared:

enum Type {
    START,
    STOP
};

我试图将枚举设置为与文件中的第一个值相同：

I'm trying to set the enum equal to the first value in the file with something like this:

enum Type foo;

ifstream ifile;
ifile.open("input.txt");

ifile >> foo;

我收到错误：在'ifile >> foo中没有匹配'operator >>' '。

I'm getting the error: no match for ‘operator>>’ in ‘ifile >> foo’.

如何正确执行此操作？

推荐答案

我发现我的特殊情况是以下代码是最好的解决方案：

I've found for my particular situation that the following code is the best solution:

template <class T> T a2e(string c, const string a[], const int size) {
    for (int i=0; i < size; i++) {
        if (c == a[i]) {
            return static_cast<T>(i);
        }
    }
}

并将使用如下：

enum StateType {START, STOP};
const int MAXVALUES = STOP+1;
const string stateNames[MAXVALUES] = {"START", "STOP"};

enum StateType state;

ifstream ifile;
ifile.open("input.txt");

ifile >> foo;
state = a2e <enum StateType> (foo, stateNames, MAXVALUES);

希望这有助于将来的人。感谢大家就如何解决这个问题提出建议。

Hope this helps someone in the future. Thanks to everyone who made suggestions about how to tackle this problem.

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