三角形（3）

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