main 中的 C++ 类循环

Question

我需要帮助以一种简单的方式解决我似乎无法使其工作的部分代码。我的“任务”的重点是所有东西都必须尝试在一个类中。现在我遇到的问题在我的代码的一部分，它假设“打印”n 个产品，这意味着它显示您在 void get() 部分中输入的内容，但我似乎无法解决的问题是它只打印最后一个产品的名称、数量、重量，而不是所有文字。

   class Class
{
public:
    string name;
    int n, amount;
    float weight;
    void market()
    {
        cout << "Give the number of products you want to get at Market : " << endl;
        cin >> n;
    }
    void get()
    {
        for (int i = 0; i < n; i++)
        {
            cout << "Give product name,amount and weight : " << endl;
            cin >> name >> amount >> weight;
        }
    }
    void print()
    {
        cout << "\nProduct display:\n" << endl;
        for (int i = 0; i < n; i++)
        {
            cout << name << " - " << amount << " , " << weight << " kg" << endl;
            cout << "------------------------" << endl;
        }
    };
};

主要部分。

int main()
    {
            Class market;
            market.market();
            market.get();
            market.print();

    }

Answer 1

您实际上是在覆盖name、amount 和weight。你必须使用类似于std::vector的东西：

class Class {
    public:
        std::vector<string> names;
        // Same for others

当您从std::cin 获取它们时，您必须将它们推入向量中：

names.push_back(name);
amounts.push_back(amount);
weights.push_back(weight);

打印时循环遍历向量：

for (int i = 0; i < n; i++) {
    cout << names[i] << " - " << amounts[i] << " , " << weights[i] << " kg" << endl;
    cout << "------------------------" << endl;
}

Answer 2

您必须使用std::vector<TYPE>（示例 1），或在单个变量中保存多个数据的数组（示例 2）。

示例 1

由于您一直使用 C++ 编程语言进行编码，因此强烈建议使用 std::vector<> 以获得最佳效果。

考虑类示例（也可以阅读 cmets）：

int count = 0; // PRIVATE SECTION
char ask;
std::vector<std::string> name;
std::vector<int> amount;
std::vector<float> weight;
std::string tName; // temp variables
int tAmount;
float tWeight;

public:

void market()
{
    cout << "WELCOME!" << endl; // nothing's required with vector
}
void get()
{
    do {
        cout << "Give product name, amount and weight : " << endl;
        cin >> tName >> tAmount >> tWeight; // getting temporary variables

        name.push_back(tName); // assigning
        amount.push_back(tAmount);
        weight.push_back(tWeight);

        count++;

        cout << "Add more? (Y/n): "; // add more? Go on if yes...
        cin >> ask;

    } while (ask == 'Y' || ask == 'y');
}
void print()
{
    cout << "\nProduct display:\n"
         << endl;
    for (int i = 0; i < count; i++)
    {
        cout << name[i] << " - " << amount[i] << " , " << weight[i] << " kg" << endl;
        cout << "------------------------" << endl;
    }
}

样本输出

WELCOME!
Give product name, amount and weight :
ABC 12 55.5
Add more? (Y/n): y
Give product name, amount and weight :
SSD 33 43.2
Add more? (Y/n): n

Product display:

ABC - 12 , 55.5 kg
------------------------
SSD - 33 , 43.2 kg
------------------------

示例 2

您只需进行少量修改即可完成相同的操作，但静态编号不被视为动态编号。您可以将数组用于您的程序，如下所述。

而不是：

string name;
int n, amount;
float weight;

考虑const int MAX = 1024; 并使用（类变量必须仅在类内部可见，其他任何地方都不可见）：

private: // declare on top of the class ("private:" is by default and redundant)
    string name[MAX];
    int n, amount[MAX];
    float weight[MAX];

编辑和工作示例类：

void get()
{
    for (int i = 0; i < n; i++)
    {
        cout << "Give product name,amount and weight : " << endl;
        cin >> name[i] >> amount[i] >> weight[i];
    }
}
void print()
{
    cout << "\nProduct display:\n"
         << endl;
    for (int i = 0; i < n; i++)
    {
        cout << name[i] << " - " << amount[i] << " , " << weight[i] << " kg" << endl;
        cout << "------------------------" << endl;
    }
}

样本输出

Give the number of products you want to get at Market :
2
Give product name,amount and weight :
ABC 25 102
Give product name,amount and weight :
BDE 22 333

Product display:

ABC - 25 , 102 kg
------------------------
BDE - 22 , 333 kg
------------------------