需要帮助修复我的程序中的小问题

Question

所以这是我的代码：

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

using namespace std;

class Point
{
private:
    double px;
    double py;

public:
    void setX(const double x);
    void setY(const double y);
    double getX() const;
    double getY() const;
};

class Rectangle
{
private:
    string name;
    Point blPoint;
    double length, height;

public:
    // member functions
    void setName(const string & inName);
    void setBottomLeft(const double x, const double y);
    void setDimensions(const double inLength, const double inHeight);

    string getName() const;
    Point getBottomLeft() const;
    double getLength() const;
    double getHeight() const;

    double area() const;
    double perimeter() const;
    Point midPoint() const;
    void scaleBy2();
    void display() const;
};

// FUNCTION PROTOTYPES GO HERE:
void welcome();
bool read_rec(const string promptName, const string errorInvalid, const string errorUsed, string & inName, vector<Rectangle> & list);
void read_coord(const string promptPoint, double & x, double & y);
void read_length(const string promptLength, double & inLength, double & inHeight);
void add_rec(const string Name, double x, double y, double inLength, double inHeight, vector<Rectangle> & list);

int main()
{
    // Define your local variables, e.g. a vector of class Rectangle
    Rectangle rec;
    vector<Rectangle> list;
    string prompt1stName = "Enter the name of the first rectangle: ";
    string promptName = "Enter the name of the next rectangle: ";
    string errorInvalid = "Invalid input. Type 'rec' following by the name or 'stop' if done.";
    string errorUsed = "This name is already being used!";
    string inName;
    string Name;

    // Display welcome banner
welcome();

    /* Prompt user for first rectangle or 'stop' */
    bool read = read_rec(prompt1stName, errorInvalid, errorUsed, inName, list);

    // WHILE user input is invalid
    while (read == false)
    {

        // Display "Try again! "
 cout << "Try again! " << endl;
         read = read_rec(prompt1stName, errorInvalid, errorUsed, inName, list);
    }

    // IF user input is not 'stop'
        if (inName != "stop")
    {
        // Extract rectangle name from user input
                int a = inName.length() - 4;
        Name = inName.substr(4, a);

        // Prompt for bottom left point
                double x, y;
        string promptPoint = "Enter " + Name + "'s bottom left x and y coords: ";
        read_coord(promptPoint, x, y);

        // Prompt for length and height
                double inLength, inHeight;
        string promptLength = "Enter " + Name + "'s length and height: ";
        read_length(promptLength, inLength, inHeight);

        // Add rectangle to the rectangle list
        add_rec(Name, x, y, inLength, inHeight, list);
    }
    /* Prompt user for next rectangle or 'stop' */
    // WHILE user input not 'stop'
        while (inName != "stop")
    {
        // Display "Thank you! "
cout << "Thank you! ";
bool read = read_rec(promptName, errorInvalid, errorUsed, inName, list);

        // WHILE user input is invalid while (read == false)
        {

            // Display "Try again! "
                        cout << "Try again! " << endl;
            read = read_rec(promptName, errorInvalid, errorUsed, inName, list);
        }

            // IF user input is not 'stop'
                    if (inName != "stop")
        {

                // Extract rectangle name from user input
                            int a = inName.length() - 4;
            Name = inName.substr(4, a);

                // Prompt for bottom left point
                            double x, y;
            string promptPoint = "Enter " + Name + "'s bottom left x and y coords: ";
            read_coord(promptPoint, x, y);

                // Prompt for length and height
                            double inLength, inHeight;
            string promptLength = "Enter " + Name + "'s length and height: ";
            read_length(promptLength, inLength, inHeight);


                // Add rectangle to the rectangle list
            add_rec(Name, x, y, inLength, inHeight, list);
        }
    }

    // IF the rectangle list is not empty
        if (list.size() != 0)
    {
        // Display all rectangles in the rectangle list
int rec_num = 0;
int i = 1;
while (i< list.size())
{
    rec_num++;
    i++;

}
            cout << "You have " << rec_num+1 << " rectangle(s) in your list: ";
            cout << endl;

                for (int i = 0; i < list.size(); i++)
        {
            cout << "Rectangle '" << list[i].getName() << "' : ";
            list[i].display();
            list[i].scaleBy2();
            cout << "     After scale by 2: ";
            list[i].display();
            cout << endl;
        }
    }

    // ELSE
    else
        {
        // Display that no rectangles are in the list
                cout << "You have no rectangles in your list." << endl;
    }

  return 0;
}

// FUNCTION DEFINITIONS GO HERE:
void welcome()
{
    cout << "Welcome! Create your own list of rectangles." << endl;
    cout << "You will be asked to provide information about each rectangle in your list by name." << endl;
    cout << "Type the word 'stop' for the rectangle name when you are done." << endl;
    cout << endl;
}

bool read_rec(const string promptName, const string errorInvalid, const string errorUsed, string & inName, vector<Rectangle> & list)
{
    cout << promptName;
    getline(cin, inName);

    if (inName == "stop")
    {
        return(true);
    }
    else if (inName.substr(0,4) != "rec ")
    {
        cout << errorInvalid;
        return(false);
    }
    else
    {
        int j = 0;
        for (int i = 0; i < list.size(); i++)
        {
            if (inName == "rec " + list[i].getName())
            {
                j = j+1;
            }
        }
        if (j == 0)
        {
            return(true);
        }
        if (j != 0)
        {
            cout << errorUsed;
            return(false);
        }
    }
}

void read_coord(const string promptPoint, double & x, double & y)
{
    cout << promptPoint;
    cin >> x;
    cin >> y;
    }

void read_length(const string promptLength, double & inLength, double & inHeight)
{
    cout << promptLength;
    cin >> inLength;
    cin >> inHeight;
    cout << endl;

    while (inLength <= 0 || inHeight <= 0)
    {
        cout << "Make length and height positive values. Try again.";
        cout << promptLength;
        cin >> inLength;
        cin >> inHeight;
        cout << endl;
    }
}

void add_rec(const string Name, double x, double y, double inLength, double inHeight, vector<Rectangle> & list)
{
    Rectangle rec;
    rec.setName(Name);
    rec.setBottomLeft(x, y);
    rec.setDimensions(inLength, inHeight);
    list.push_back(rec);
}

// CLASS MEMBER FUNCTION DEFINITINOS GO HERE:

void Point::setX(const double x)
{
    px = x;
}

void Point::setY(const double y)
{
    py = y;
}

double Point::getX() const
{
    return (px);
}

double Point::getY() const
{
    return (py);
}

void Rectangle::setName(const string & inName)
{
    name = inName;
}

void Rectangle::setBottomLeft(const double x, const double y)
{
    blPoint.setX(x);
    blPoint.setY(y);
}

void Rectangle::setDimensions(const double inLength, const double inHeight)
{
    length = inLength;
    height = inHeight;
}

string Rectangle::getName() const
{
    return (name);
}

Point Rectangle::getBottomLeft() const
{
    return (blPoint);
}

double Rectangle::getLength() const
{
    return (length);
}

double Rectangle::getHeight() const
{
    return (height);
}

double Rectangle::area() const
{
    // area = length * height
    return(length * height);
}

double Rectangle::perimeter() const
{
    // perimeter = 2 * (length + height);
    return(2 * (length + height));
}

Point Rectangle::midPoint() const
{
    Point midPoint;
    double mx = blPoint.getX() + 0.5 * length;
    double my = blPoint.getY() + 0.5 * height;
    midPoint.setX(mx);
    midPoint.setY(my);
    return(midPoint);
}

void Rectangle::scaleBy2()
{
    double midx = blPoint.getX() + 0.5 * length;
    double midy = blPoint.getY() + 0.5 * height;
    double newblPx = midx - length;
    double newblPy = midy - height;
    length = 2*length;
    height = 2*height;
    blPoint.setX(newblPx);
    blPoint.setY(newblPy);
}

void Rectangle::display() const
{
    cout << " Location is (" << blPoint.getX() << ", " << blPoint.getY() << "), length is " << length << ", height is " << height << "; Area is " << area() << "; perimeter is " << perimeter() << ", midpoint is located at (" << midPoint().getX() << ", " << midPoint().getY() << ")" << endl;
}

我现在对程序的唯一问题是它总是输出“无效输入。输入'rec'后跟名称或'stop'如果完成。”，我不知道如何改变它。当你在rec fire和rec fire中输入一个重复的答案时，它会说rec fire已被使用，然后继续提示该矩形，而不是要求另一个名字。任何帮助将非常感谢!!

Answer 1

这是错误的

/* Prompt user for first rectangle or 'stop' */
bool read = read_rec(prompt1stName, errorInvalid, errorUsed, inName, list);

// WHILE user input is invalid
while (read == false)
{

    // Display "Try again! "
    cout << "Try again! " << endl;
    bool read = read_rec(prompt1stName, errorInvalid, errorUsed, inName, list);
}

你有两个读取变量，while条件中的read变量指的是声明 first 的读取变量，从不使用声明为second的读取变量。你想要的是这个

/* Prompt user for first rectangle or 'stop' */
bool read = read_rec(prompt1stName, errorInvalid, errorUsed, inName, list);

// WHILE user input is invalid
while (read == false)
{

    // Display "Try again! "
    cout << "Try again! " << endl;
    read = read_rec(prompt1stName, errorInvalid, errorUsed, inName, list);
}

现在你只有一个读变量。这说明了我想到的第二个错误。

另一种编码方式就是这样

for (;;)
{
    bool read = read_rec(prompt1stName, errorInvalid, errorUsed, inName, list);
    if (read)
        break;
    cout << "Try again! " << endl;
}

在我看来，这种循环更好，因为它没有对read_rec的重复调用，所以使用这种循环方式你所犯的错误是不可能的。