Question

我正尝试使用向量迭代器按列输出我的字符串，如下图所示。现在，我仅显示一个使用名称和苹果酒顺序的测试用例，然后再将其复制给其他人。 Desired output screenshot

下面是我当前的代码：

// values for controlling format
const int name_width = 15 ;
const int int_width = 7 ;
const int dbl_width = 12 ;
const int num_flds = 7 ;
const std::string sep = " |" ;
auto total_width = name_width*2 + int_width*2 + dbl_width*3 + sep.size() * num_flds ;
const std::string line = sep + std::string( total_width-1, '-' ) + '|' ;

cout<<"How many people ordered? ";
cin>>odrs; // Store number of orders

for(int i=1; i<=odrs; i++){
    cout<<"Enter the name of person #"<<i<<":"<<endl;;
    cin>>names;  // Store names of users

    odrNames.push_back(names);  // Store names as entered as

    cout<<"How many orders of cider did "<<names<<" have? ";
    cout<<endl;
    cin>>odrciderjuice;  // Store Cider order item
    sbCider = odrciderjuice * 5.5;    // Calculate Cider order per price
    odrCider.push_back(odrciderjuice); // Store Cider order item based on entry
    SbCider.push_back(sbCider);      // Store calculated Cider order per price

    cout<<"How many orders of apple juice did "<<names<<" have? ";
    cout<<endl;
    cin>>odrapplejuice;     // Store Juice order item
    sbJuice = odrapplejuice * 4.5;    // Calculate Juice order per price
    odrApple.push_back(odrapplejuice);     // Store Juice order item based on entry
    SbJuice.push_back(sbJuice);      // Store calculated Juice order per price
    cout<<endl;

    total = sbCider + sbJuice;   // Calculate total between Cider and Juice
    GTotal.push_back(total);     // Store total values after calculation
    cout<<endl;
}

for(vector<string>::iterator naming = odrNames.begin(); naming!= odrNames.end(); ++naming)
    cout << sep << std::setw(name_width) << *naming<<"\v";

for(vector<int>::iterator ciderOdr = odrCider.begin(); ciderOdr!= odrCider.end(); ++ciderOdr)
    cout <<*ciderOdr;

Answer 1

使用迭代器确实是浏览集合的惯用方式。简单来说，您需要一个对象集合，而不是一堆无关的集合！

此外，您应该在名称上保持一致，并且仅在单个值及其集合之间使用大写是将来维护的噩梦...

C ++是一种OO语言，而OO编程是一种将复杂程序拆分为较小单元（类）的方法，这些较小单元仅对较大程序的一小部分负责。这是为了使代码更易于测试和维护。

Order类可以包含：

客户名称的一个字符串
苹果酒和果汁数量的2个整数
可选的计算详细价格和总价格的方法

由于您的格式设置并不简单，因此我将使用备用类来处理它。该类将包含：

对vector<Order>的引用
对ostream的引用
静态元素以获取格式详细信息
显示标题行，水平虚线，订单行以及总计和平均行的方法。

然后主体将仅包含用于加载订单的代码。

代码可能是：

#include <iostream>
#include <string>
#include <vector>
#include <iomanip>

using namespace std;

struct Order {
    static constexpr double ciderPrice = 5.5;
    static constexpr double juicePrice = 4.5;
    std::string name;
    int cider;
    int juice;

    double sbCider() const {
        return cider * ciderPrice;
    }
    double sbJuice() const {
        return juice * juicePrice;
    }
    double total() const {
        return sbCider() + sbJuice();
    }
};

class Bill {
    // values for controlling format
    static const int name_width = 10 ;
    static const int int_width = 6 ;
    static const int dbl_width = 17 ;

    const std::vector<Order>& orders;
    std::ostream& out;

    ...

public:
    Bill(const std::vector<Order>& orders, std::ostream& out):orders(orders),out(out) { }
    Bill& show_line() {
        ...
        return *this;
    }
    Bill& show_header() {
        ...
        return *this;
    }
    Bill& show_order(const Order &order) {
        ...
        return *this
    }
    Bill& show_total() {
        return *this
    }
    Bill &show_average() {
        ...
        return *this;
    }
    Bill& show() {
        ...
        show_header().show_line();
        for (const Order& order: orders) {
            show_order(order);
        }
        return show_line().show_total().show_average().show_line();
    }
};
int main() {
Order order;
vector<Order> orders;

int odrs;

cout<<"How many people ordered? ";
cin>>odrs; // Store number of orders

for(int i=1; i<=odrs; i++){
    cout<<"Enter the name of person #"<<i<<":"<<endl;;
    cin>>order.name;  // Store names of users

    cout<<"How many orders of cider did "<<order.name<<" have? "<<endl;
    cin>>order.cider;  // Store Cider order item

    cout<<"How many orders of apple juice did "<<order.name<<" have? "<<endl;
    cin>>order.juice;     // Store Juice order item
    orders.push_back(order);
}

Bill bill(orders, std::cout);
bill.show();
return 0;   
}

C ++向量迭代器输出垂直显示在列中

1 个答案: