c++ - 我哪里错了？我收到链接器错误( undefined symbol )，我被卡住了

Question

这个问题在这里已经有了答案:





What is an undefined reference/unresolved external symbol error and how do I fix it?

(37 个回答)


1年前关闭。




我反复收到此错误消息，我不知道为什么。
我尝试在网上查找，发现此错误消息来自链接器，而不是编译器，它试图告诉我我没有链接到库或目标代码。也许我错过了一个变量？我不知道。
这是代码:

class foodType
{
public:
    void set(string, int, double, int, double, double);
    void print() const;
    foodType(string = "", int = 0, double = 0.0, int = 0, double = 0.0, double = 0.0);
    
private:
    string name;
    int calories;
    double fat;
    int sugar;
    double carbohydrate;
    double potassium;
};

foodType apple;

int main()
{
    apple.set( "Apple" , 100, 0.10, 10, 100.00, 0.02);
    apple.print();

    return 0;
}

void foodType::set(string fruitName, int Cal, double fats,
                        int sug, double carbs, double K)
{
    name = fruitName;
    calories = Cal;
    fat = fats;
    sugar = sug;
    carbohydrate = carbs;
    potassium = K;
}

void foodType::print() const
{
    cout << "Fruit is: "        << name << endl;
    cout << "Calories: "        << calories << endl;
    cout << "Fat content: "     << fat << endl;
    cout << "Sugar content: "   << sugar << endl;
    cout << "Carbs: "           << carbohydrate << endl;
    cout << "Potassium: "       << potassium << endl;
}

Answer 1

您缺少 foodType::foodType 的定义.