我哪里出错了？我收到链接器错误(未定义的符号)并且卡住了

Question

我反复收到这个错误消息，我不知道为什么。我试着在网上查找，发现这个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。也许我遗漏了一个变量？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。