第五周实验报告 任务一

源代码：

//默认构造函数#include<iostream>#include<cmath>using namespace std;class Triangle{public:Triangle(float x = 1, float y = 1, float z = 1);//Triangle(float x, float y, float 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;if((a + b > c && a + c > b && b + c > a) && (a - b < c && a - c < b && b - c < a)){cout<<"该三角形的周长为："<< perimeter()<<'\t'<<"面积为："<< area()<<endl;}else{cout<< "三边无法构成三角形!!!" << endl;}}float Triangle::perimeter(void){float d;d = a + b + c;return d;}float Triangle::area(void){float p = (a + b + c) / 2;float m = sqrt(p*(p-a)*(p-b)*(p-c));  return m;}Triangle::Triangle(float x, float y, float z){a = x;b = y;c = z;}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();Triangle Tri3(2);Tri3.showMessage();}//带参数的构造函数#include<iostream>#include<cmath>using namespace std;class Triangle{public:/*Triangle(){ a = 1;b = 1;c = 1;}*/Triangle(float x, float y, float 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;if((a + b > c && a + c > b && b + c > a) && (a - b < c && a - c < b && b - c < a)){cout<<"该三角形的周长为："<< perimeter()<<'\t'<<"面积为："<< area()<<endl;}else{cout<< "三边无法构成三角形!!!" << endl;}}float Triangle::perimeter(void){float d;d = a + b + c;return d;}float Triangle::area(void){float p = (a + b + c) / 2;float m = sqrt(p*(p-a)*(p-b)*(p-c));  return m;}Triangle::Triangle(float x, float y, float z){a = x;b = y;c = z;}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();}//使用参数初始化表对成员函数初始化#include<iostream>#include<cmath>using namespace std;class Triangle{public:Triangle(){ a = 1;b = 1;c = 1;}Triangle(float x, float y, float z):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;if((a + b > c && a + c > b && b + c > a) && (a - b < c && a - c < b && b - c < a)){cout<<"该三角形的周长为："<< perimeter()<<'\t'<<"面积为："<< area()<<endl;}else{cout<< "三边无法构成三角形!!!" << endl;}}float Triangle::perimeter(void){float d;d = a + b + c;return d;}float Triangle::area(void){float p = (a + b + c) / 2;float m = sqrt(p*(p-a)*(p-b)*(p-c));  return m;}/*Triangle::Triangle(float x, float y, float z){a = x;  b = y;  c = z;}*/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();}

截图：

收获：理解了构造函数在类里的应用···收获不小···

感想：一开始没弄清题意···后来好了~开心哈~