使用输入字符串作为变量名

问题描述

如果输入的是例如"banana"，我想打印出香蕉的千卡.我尝试过类似的操作(但失败了):

If the input is for example "banana", I want to print the kcal of banana. I tried something like this (and failed):

string input;
cin >> input;
cout << input.Kcal << endl;

我知道我可以使用if语句来做到这一点

I know that I can do it with if-statements like:

string input;
cin >> input;

if(input == "banana")
{
    cout << banana.Kcal << endl;
}

但是当我有1000多种食物时，我必须编写很多代码...

But there I must write very much code when I have more then 1000 foods...

有我对香蕉对象的声明和定义.每个对象都有千卡.

There is my declaration and definition of my banana object. Every object has kcal.

food banana;
banana.Kcal = 89;

我的班级，Food.h代码:

My class, the Food.h code:

#pragma once

class CFood
{
public:
    CFood();
    ~CFood();
    float Kcal;
}

food.cpp代码:

The food.cpp code:

CFood::CFood()
{
    Kcal = 0;
}
CFood::~CFood()
{
}

推荐答案

将所有食物存储在 std :: map 或相关容器中，并通过其 string 进行访问.code>键:

Store all of your foods in a std::map or related container, and access them by their string key:

std::map<string, Food> Foods;
Foods.insert(std::make_pair("banana", Banana));

// later..

cin >> stuff;
cout << Foods.at(stuff).kcal << endl;

请记住，以上内容是伪的，您通常需要采取一些保护措施来保护您的项目免于崩溃(例如，检查 Foods.find(stuff)！= Foods.end()等)

Keep in mind that the above is pseudo, and you'd typically want to make some safeguards to protect your project from crashing (e.g., checking for Foods.find(stuff) != Foods.end(), etc.)

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