C++三角形类实现-优快云博客

本文链接：https://blog.youkuaiyun.com/liu13479526389/article/details/70658531

本文介绍了使用C++实现三角形类的过程，包括构造函数、成员函数如计算周长和面积的方法，并展示了如何通过不同构造方式创建三角形对象及其属性验证。

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（一）问题及代码：

#include <iostream>
#include<cmath>
using namespace std;
class Triangle
{
public:
    void setABC(double x,double y,double z);
    double perimeter();
    double area();
private:
    double a,b,c;

};
int main()
{
   Triangle tri1;
   tri1.setABC(4,5,6);
   cout<<"三角形周长:"<<tri1.perimeter()<<'\t'<<"面积为:"<<tri1.area()<<endl;
return 0;
}
void Triangle::setABC(double x,double y,double z)
{
    a=x;
    b=y;
    c=z;
}
double Triangle::perimeter()
{
    return a+b+c;
}
double Triangle::area()
{
    double z;
    z=0.5*(a+b+c);

return sqrt(z*(z-a)*(z-b)*(z-c));
}

（二）运行结果：

（三）问题及代码：

#include <iostream>
#include<cmath>
using namespace std;
class Triangle
{
public:
Triangle(double x=1,double y=1,double z=1)
{a=x;b=y;c=z;}
    double area();
    double perimeter();
    bool isTriangle()
    {
        if(a+b>c&&b+c>a&&a+c>b)
            return true;
        else return false;
    }
    double getA()
    {
        return a;
    }
    double getB()
    {
        return b ;
    }
    double getC()
    {
        return c;
    }
void showmessage();
private:
    double a,b,c;
};
double Triangle::perimeter()
{
    return a+b+c;
}
double Triangle::area()
{
    double z;
z=((a*a+b*b-c*c)/(2*a*b));
return 0.5*a*b*sqrt((1-z*z));
}
void Triangle::showmessage()
{
      if(isTriangle())
   {
   cout<<"三条边为:"<<getA()<<','<<getB()<<','<<getC()<<endl;
   cout<<"三角形的周长为:"<<perimeter()<<'\t'<<"面积为:"<<area()<<endl;
   }
   else
    cout<<"不能构成三角形"<<endl;
}
int main()
{
   Triangle Tri1(7,8,9);
   Tri1.showmessage();
   return 0;
}

（四）运行结果：

（五）问题及代码：

#include <iostream>
#include<cmath>
using namespace std;
class Triangle
{
public:
Triangle(double x=1,double y=1,double z=1)
{a=x;b=y;c=z;}
Triangle (Triangle &p);
    double area();
    double perimeter();
    bool isTriangle()
    {
        if(a+b>c&&b+c>a&&a+c>b)
            return true;
        else return false;
    }
    double getA()
    {
        return a;
    }
    double getB()
    {
        return b ;
    }
    double getC()
    {
        return c;
    }
void showmessage();
private:
    double a,b,c;
};
Triangle::Triangle (Triangle &p)
{
    a=p.a;
    b=p.b;
    c=p.c;
}
double Triangle::perimeter()
{
    return a+b+c;
}
double Triangle::area()
{
    double z;
z=((a*a+b*b-c*c)/(2*a*b));
return 0.5*a*b*sqrt((1-z*z));
}
void Triangle::showmessage()
{
      if(isTriangle())
   {
   cout<<"三条边为:"<<getA()<<','<<getB()<<','<<getC()<<endl;
   cout<<"三角形的周长为:"<<perimeter()<<'\t'<<"面积为:"<<area()<<endl;
   }
   else
    cout<<"不能构成三角形"<<endl;

}
int main()
{
   Triangle Tri1(7,8,9);
   Tri1.showmessage();
   Triangle Tri2(Tri1);
   Tri2.showmessage();
   return 0;
}

（六）运行结果：

（七）问题及代码：
#include <iostream>
#include<cmath>
using namespace std;
class Triangle
{
public:
Triangle(double x=1,double y=1,double z=1)
{a=x;b=y;c=z;}
    double area();
    double perimeter();
    bool isTriangle()
    {
        if(a+b>c&&b+c>a&&a+c>b)
            return true;
        else return false;
    }
    double getA()
    {
        return a;
    }
    double getB()
    {
        return b ;
    }
    double getC()
    {
        return c;
    }
void showmessage();
private:
    double a,b,c;
};
double Triangle::perimeter()
{
    return a+b+c;
}
double Triangle::area()
{
    double z;
z=((a*a+b*b-c*c)/(2*a*b));
return 0.5*a*b*sqrt((1-z*z));
}
void Triangle::showmessage()
{
      if(isTriangle())
   {
   cout<<"三条边为:"<<getA()<<','<<getB()<<','<<getC()<<endl;
   cout<<"三角形的周长为:"<<perimeter()<<'\t'<<"面积为:"<<area()<<endl;
   }
   else
    cout<<"不能构成三角形"<<endl;
}
int main()
{
   Triangle Tri1;
     Tri1.showmessage();
     Triangle Tri2(1.5);
     Tri2.showmessage();
     Triangle Tri3(1.5,1.5);
     Tri3.showmessage();
    Triangle Tri4(7,8,9);
     Tri4.showmessage();
   return 0;
}