#include <iostream> #include <cmath> using namespace std; class Triangle { public: Triangle (float x = 1 , float y =1, float z = 1):a(x), b(y), c(z) {} float perimeter(void);//计算三角形的周长 float area(void);//计算并返回三角形的面积 void showMessage(); private: float a, b, c; //三边为私有成员数据 }; void Triangle::showMessage() { cout << "三角形的三边长分别为:"<< a << " "<< b <<" "<< c << endl; cout << "该三角形的周长为:" << perimeter() << '\t'<< "面积为:" << area() << endl << endl; } void main(void) { Triangle Tri1; //定义三角形类的一个实例(对象) Tri1.showMessage(); Triangle Tri2(7, 8, 9); //定义三角形类的一个实例(对象) Tri2.showMessage(); system ("pause"); } float Triangle::perimeter() { return a + b + c; } float Triangle::area() { float p = (a + b + c) / 2; return sqrt (p * (p - a) * (p - b) * (p - c)); }