第五周 项目一 三角形类雏形（3）

问题及代码：

设计三角形类带参数的构造函数，即Triangle(double x,double y,double z),三边长在调用时由实参直接给出。  */    #include <iostream>  #include <cmath>  using namespace std;  class Triangle  {  public:      Triangle(double x, double y, double z): a(x),b(y),c(z) {}//构造函数        void setABC(double x, double y, double z);      double perimeter();//计算三角形周长      double area();//计算三角形面积      void setA(double x) {a = x;}      void setB(double y) {b = y;}      void setC(double z) {c = z;}      double getA() {return a;}      double getB() {return b;}      double getC() {return c;}        void showMessage();//三角形信息    private:      double a,b,c;  };  void Triangle::showMessage()  {            cout << "三条边为：" <<a<< "," <<b<< "," <<c<< endl;          cout << "三角形的周长为：" <<perimeter() << "\t" << "面积为：" <<area() << endl;  }  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 p = (a+b+c)/2;     return sqrt(p*(p-a)*(p-b)*(p-c));  };  int main()  {     Triangle tri(7,8,9);     tri.showMessage();      return 0;  }  

运行结果：