class Triangle { public: void setA(double x){a=x;}; //内置函数要定义在头文件中 void setB(double y){b=y;}; void setC(double z){c=z;}; double getA(){return a;} double getB(){return b;} double getC(){return c;} bool isTriangle();//判断是否构成三角形 double perimeter(void);//计算三角形的周长 double area(void);//计算并返回三角形的面积 private: double a,b,c; //三边为私有成员数据 }; bool Triangle::isTriangle() { return (a+b>c&&a+c>b&&b+c>a); } 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)); }
#include<iostream> #include "Triangle.h" using namespace std; int main() { Triangle tri1; //定义三角形类的一个实例(对象) double x,y,z; cout<<"请输入三角形的三边:"; cin>>x>>y>>z; tri1.setA(x);tri1.setB(y);tri1.setC(z); //为三边置初值 if(tri1.isTriangle()) { cout<<"三条边为:"<<tri1.getA()<<','<<tri1.getB()<<','<<tri1.getC()<<endl; cout<<"三角形的周长为:"<< tri1.perimeter()<<'\t'<<"面积为:"<< tri1.area()<<endl; } else cout<<"不能构成三角形"<<endl; system("pause"); return 0; }