c++例题构造函数（一）

【项目1拓展（选做）】请自行设计一个矩形类，可以计算矩形的面积、周长、对象线，判断是否是正方形。请用上类似的构造函数，自己设计main()函数，对设计的类进行测试。

[cpp]
#include <iostream>
#include <cmath>
using namespace std;

class Rectangle
{
private:
    double length;
    double width;
public:
    Rectangle():length(1),width(1){}
    Rectangle(double len,double wid):length(len),width(wid){}
//   Rectangle(double len=1,double wid =1):length(len),width(wid){}

    double area(void);
    double perimeter(void){ return 2*(length+width); }
    double diagonal(void) { return sqrt(length*length+width*width); }

    bool square_or_not(void) { return length==width?true:false; }
    void show_message(void);
};

//Rectangle::Rectangle(double len,double wid){length = len;width = wid;}

double Rectangle::area(void)
{
    return length*width;
}

void Rectangle::show_message(void)
{
    cout << "矩形的长宽分别为: " << length << '\t' << width <<endl;
    cout << "周长: " << perimeter() << "面积: " << area() << "对角线长度: "<< diagonal() << endl;
    cout << "是否为正方形? " << square_or_not() << endl;

}

int main()
{
    Rectangle rect1;
    rect1.show_message();

    Rectangle rect2(3,4);
    rect2.show_message();

    return 0;
}

#include <iostream>
#include <cmath>
using namespace std;

class Rectangle
{
private:
double length;
double width;
public:
Rectangle():length(1),width(1){}
Rectangle(double len,double wid):length(len),width(wid){}
// Rectangle(double len=1,double wid =1):length(len),width(wid){}

double area(void);
double perimeter(void){ return 2*(length+width); }
double diagonal(void) { return sqrt(length*length+width*width); }

bool square_or_not(void) { return length==width?true:false; }
void show_message(void);
};

//Rectangle::Rectangle(double len,double wid){length = len;width = wid;}

double Rectangle::area(void)
{
return length*width;
}

void Rectangle::show_message(void)
{
cout << "矩形的长宽分别为: " << length << '\t' << width <<endl;
cout << "周长: " << perimeter() << "面积: " << area() << "对角线长度: "<< diagonal() << endl;
cout << "是否为正方形? " << square_or_not() << endl;

}

int main()
{
Rectangle rect1;
rect1.show_message();

Rectangle rect2(3,4);
rect2.show_message();

return 0;
}

补充：软件开发 , C++ ,

c++例题 构造函数（一）

c++例题构造函数（一）