#include<iostream>
#include<Cmath>
using namespace std;
class Triangle
{
public:
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;
}
int isTriangle();
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
};
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;
return 0;
}
int Triangle::isTriangle()
{
return (a + b > c&&a + c > b&&b + c > a);
}
double Triangle::perimeter()
{
return a + b + c;
}
double Triangle::area()
{
double p;
p = (a + b + c) / 2;
return sqrt(p*(p - a)*(p - b)*(p - c));
}第三周项目-2
原文：http://blog.csdn.net/zhouwengong/article/details/45176181
