C++三角形程序：未填充时Color输出N/A的实现求助

需求：当用户输入0表示三角形未填充时，程序的Color字段需输出N/A，当前代码在if (filled == 0)块中不知道如何处理。期望输出示例：

Input the length of three sides of the triangle: 5 5 5 
Enter whether the triangle is filled (1) or not (0): 0
Color: N/A
Area: 10.8253
Perimeter: 15

当前代码如下：

#include <iostream>
#include <math.h>
using namespace std;
//triangle class toperform all the operation on a triangle
class Triangle
{
    double side1, side2, side3; //private variable storing sides of triangle

public:
    bool filled;
    string color;
    //default constructor
    Triangle()
    {
        this->side1 = 1.0;
        this->side2 = 1.0;
        this->side3 = 1.0;
    }
    //constructor two initialize sides of tiangle with the given value
    Triangle(double one, double two, double three)
    {
        this->side1 = one;
        this->side2 = two;
        this->side3 = three;
    }
    //function to return perimiter of triangle
    double getPerimeter()
    {
        return this->side1 + this->side2 + this->side3;
    }
    //function to return area of triangle
    double getArea()
    {
        double p = getPerimeter() / 2;
        double area = p * (p - this->side1) * (p - this->side2) * (p - this->side3);
        return sqrt(area);
    }
};
int main()
{
    double a, b, c;
    int filled;
    string col = "";
    cout << "Input the length of three sides of the triangle: ";
    cin >> a >> b >> c;
    Triangle triObj(a, b, c);
    cout << "Enter whether the triangle is filled (1) or not (0): ";
    cin >> filled;
    triObj.filled = filled;
    if (filled == 1)
    {
        cout << "Enter the colour of the triangle: ";
        cin >> col;
        triObj.color = col;
    }

    if (filled == 0)
    {
        //Need help with this
    }

    cout << "Color: " << triObj.color;
    cout << "\nArea: " << triObj.getArea();
    cout << "\nPerimeter: " << triObj.getPerimeter() << '\n';
    cout << "\nWas the triangle filled?: ";
    if (triObj.filled)
        cout << "True\n";
    else
        cout << "False\n";

}

有两种简洁的实现方式：

方式一：输出时直接判断填充状态 #

不需要修改if (filled == 0)块，直接在输出Color的位置添加条件判断，逻辑更清晰：

// 替换原有的cout << "Color: " << triObj.color;
cout << "Color: ";
if (triObj.filled) {
    cout << triObj.color;
} else {
    cout << "N/A";
}

方式二：在未填充分支中给color赋值 #

如果希望triObj.color本身存储N/A，直接在空的if块中赋值即可：

if (filled == 0)
{
    triObj.color = "N/A";
}

修改后的完整main函数（以方式一为例） #

int main()
{
    double a, b, c;
    int filled;
    string col = "";
    cout << "Input the length of three sides of the triangle: ";
    cin >> a >> b >> c;
    Triangle triObj(a, b, c);
    cout << "Enter whether the triangle is filled (1) or not (0): ";
    cin >> filled;
    triObj.filled = filled;
    if (filled == 1)
    {
        cout << "Enter the colour of the triangle: ";
        cin >> col;
        triObj.color = col;
    }

    // 输出Color时判断填充状态
    cout << "Color: ";
    if (triObj.filled) {
        cout << triObj.color;
    } else {
        cout << "N/A";
    }
    cout << "\nArea: " << triObj.getArea();
    cout << "\nPerimeter: " << triObj.getPerimeter() << '\n';
    cout << "\nWas the triangle filled?: ";
    if (triObj.filled)
        cout << "True\n";
    else
        cout << "False\n";

}

内容的提问来源于stack exchange，提问作者user20544996