我创建了一个RentalAgency结构，其中包含名称，邮政编码和库存。我还创建了一个包含库存成员的RentalCar类。我试图将数据从文本文件读入各个位置，但遇到了麻烦。
struct RentalAgency {
char name[25]; //25 characters max
int zipcode[5]; //5 digits in zipcode
RentalCar inventory[5]; //5 cars
};
class RentalCar {
int m_year;
char m_make[256], m_model[256]; //256 characters max
float m_price;
bool m_available;
public:
RentalCar();
RentalCar(int, char[], char[], float, bool);
void setYear(int);
void setMake(char[]);
void setModel(char[]);
void setPrice(float);
void setAvailable(bool);
int getYear();
char* getMake();
char* getModel();
float getPrice();
bool getAvailable();
void print();
float estimateCost(int);
};
我正在尝试从此文本文件中读取。
Hertz 93619
2014 Toyota Tacoma 115.12 1
2012 Honda CRV 85.10 0
2015 Ford Fusion 90.89 0
2013 GMC Yukon 110.43 0
2009 Dodge Neon 45.25 1
Alamo 89502
2011 Toyota Rav4 65.02 1
2012 Mazda CX5 86.75 1
2016 Subaru Outback 71.27 0
2015 Ford F150 112.83 1
2010 Toyota Corolla 50.36 1
Budget 93035
2008 Ford Fiesta 42.48 0
2009 Dodge Charger 55.36 1
2012 Chevy Volt 89.03 0
2007 Subaru Legacy 59.19 0
2010 Nissan Maxima 51.68 1
到目前为止，我已经设置了一个读取数据的功能。我已经成功创建了一个for循环，该循环读取了Rental Agency的名称，但是在邮政编码方面我陷入了困境。
void input(struct RentalAgency data[])
{
char inputFile[50]; //50 characters max
char tmp;
std::ifstream inputStream;
std::cout << "Enter input file name: ";
std::cin >> inputFile;
inputStream.open(inputFile);
for(int i = 0; i < 3; i++) //3 agencies
{
inputStream >> data[i].name;
for(int j = 0; j < 5; j++)
{
inputStream >> tmp;
data[i].zipcode[j] = tmp;
}
}
}
我打印数据时的输出是：
data[0].name = Hertz //correct
data[0].zipcode[0] = 57 //wrong
data[0].zipcode[1] = 51 //wrong
data[0].zipcode[2] = 54 //wrong
data[0].zipcode[3] = 49 //wrong
data[0].zipcode[4] = 57 //wrong
我想要的是：
data[0].zipcode[0] = 9
data[0].zipcode[1] = 3
data[0].zipcode[2] = 6
data[0].zipcode[3] = 1
data[0].zipcode[4] = 9
答案 0 :(得分：0)
您要在邮政编码中存储字符0-9的{{3}}值。您需要从读取的字符中减去0的ASCII值：
for(int j = 0; j < 5; j++)
{
inputStream >> tmp;
data[i].zipcode[j] = tmp - '0';
}
答案 1 :(得分：0)
请在下面找到一个完整的可行解决方案，包括您的讲师的无意义限制。
所以，我们在这里做，通常没人会做。
该程序严格依赖于确切的输入格式，这也不是很好。
更灵活的方法会更好
#include <iostream>
#include <sstream>
#include <fstream>
#include <iterator>
#include <algorithm>
std::istringstream inputFile{ R"(Hertz 93619
2014 Toyota Tacoma 115.12 1
2012 Honda CRV 85.10 0
2015 Ford Fusion 90.89 0
2013 GMC Yukon 110.43 0
2009 Dodge Neon 45.25 1
Alamo 89502
2011 Toyota Rav4 65.02 1
2012 Mazda CX5 86.75 1
2016 Subaru Outback 71.27 0
2015 Ford F150 112.83 1
2010 Toyota Corolla 50.36 1
Budget 93035
2008 Ford Fiesta 42.48 0
2009 Dodge Charger 55.36 1
2012 Chevy Volt 89.03 0
2007 Subaru Legacy 59.19 0
2010 Nissan Maxima 51.68 1
)" };
constexpr size_t MakeAndModelSize = 256;
constexpr size_t MaxInputLineSize = 1024;
constexpr size_t ZipCodeSize = 5;
constexpr size_t InventorySize = 5;
constexpr size_t NameOfAgenySize = 25;
class RentalCar {
public:
RentalCar() {
std::fill(m_make, m_make + MakeAndModelSize, 0);
std::fill(m_model, m_model + MakeAndModelSize, 0);
};
RentalCar(int y, char* make, char* model, float price, bool available) : m_year(y), m_price(price), m_available(available) {
std::copy_n(make, MakeAndModelSize, m_make);
std::copy_n(model, MakeAndModelSize, m_model);
}
// I am breaking the whole encapsulation
// We make some more noensense and define setters and getters for everything.
// so, we can also make all data public . . .
void setYear(int year) { m_year = year; }
void setMake(char* make) { std::copy_n(make, MakeAndModelSize, m_make); }
void setModel(char* model) { std::copy_n(model, MakeAndModelSize, m_model); }
void setPrice(float price) { m_price = price; }
void setAvailable(bool avail) { m_available = avail; }
int getYear() { return m_year; };
char* getMake() { return m_make; };
char* getModel() { return m_model; }
float getPrice() { return m_price; }
bool getAvailable() { return m_available; };
void print() { std::cout << *this; } // This function is not needed. We overlaoded the inserter already for that purpose
double estimateCost(int days) { return days * m_price * (m_available ? 1.0 : 0.0);}
// Overload inserter and extractor
friend std::ostream& operator << (std::ostream& os, const RentalCar& rc) {
return os << rc.m_year << ' ' << rc.m_make << ' ' << rc.m_model << ' ' << rc.m_price << ' ' << rc.m_available;
}
friend std::istream& operator >> (std::istream& is, RentalCar& rc) {
is >> rc.m_year >> rc.m_make >> rc.m_model >> rc.m_price >> rc.m_available;
return is;
}
protected:
// The data of the car
int m_year{};
char m_make[MakeAndModelSize]; // Lord, forgive me, I am using a fixed size plain char array for a string
char m_model[MakeAndModelSize]; // Lord, forgive me, I am using a fixed size plain char array for a string
float m_price{ 0.0 };
bool m_available{ false };
};
class RentalAgency {
public:
// Extractor operator. Read all data from stream
friend std::istream& operator >> (std::istream& is, RentalAgency& ra) {
is >> ra.name ;
std::copy_n(std::istream_iterator<char>(is), ZipCodeSize, ra.zipcode);
// Read all inventory data
std::copy_n(std::istream_iterator<RentalCar>(is), InventorySize, ra.inventory);
return is;
}
// Inserter operator. Output Data
friend std::ostream& operator << (std::ostream& os, const RentalAgency& ra) {
// Show name and zip code
os << ra.name << ' ';
std::copy_n(ra.zipcode, ZipCodeSize, std::ostream_iterator<char>(os));
os << '\n';
// Print inventory data
std::copy_n(ra.inventory, InventorySize, std::ostream_iterator<RentalCar>(os, "\n"));
return os << '\n';
}
protected:
char name[NameOfAgenySize]{};
int zipcode[ZipCodeSize]{};
RentalCar inventory[InventorySize]{};
};
int main()
{
RentalAgency ra1{};
RentalAgency ra2{};
RentalAgency ra3{};
// Read all data
inputFile >> ra1 >> ra2 >> ra3;
// For verification. Write all data to std::cout
std::cout << ra1 << ra2 << ra3;
return 0;
}
请注意。我正在重载类的提取器和插入器运算符。这样，阅读和写作就变得非常容易。请参阅主要内容。
然后我从istringstream中读取。但这与从文件读取相同。因此，这里没有文件，所以我选择此解决方案。