🎯第一题：
现有一学生类定义, 分别实现类的构造函数、拷贝构造函数(深拷贝)、析构函数及显示函数;分别用构造函数及拷贝构造函数创建对象，并输出对象信息。效果如图：
🎯 第二题：
声明一个Student类，在该类中包括数据成员name(姓名)，score(分数)、两个静态数据成员total_score(总分)和count(学生人数)；一个静态成员函数average()用于求全班成绩的平均值。在main函数中，输入某班(3个)同学的姓名成绩，输出全班学生的成绩之和及平均分。效果如图：
🎯 第三题：
设计一个坐标系点类Point，友元函数dis计算给定两个坐标点的距离；在主程序中创建类Point的两个点对象p1和p2；计算两个点之间距离并输出。效果如图:
🎯 答案：
💻第一题：
#include <iostream> #include <cstring> using namespace std; class Student { public: Student(int id,string name,char* addr); Student(const Student& other); ~Student(); void show(); private: int _id; string _name; char *_addr; }; Student::Student(int id,string name,char* addr) { cout<<"调用构造函数"<<endl; _id=id; _name=name; int len =strlen(addr)+1; _addr=new char[len]; memset(_addr,0,len); strcpy(_addr,addr); } Student::Student(const Student& another) { cout<<"调用拷贝构造函数"<<endl; _id=another._id; _name=another._name; int len=strlen(another._addr)+1; _addr=new char[len]; strcpy(_addr,another._addr); } void Student::show() { cout<<_id<<" "<<_name<<" "<<_addr<<endl; } Student::~Student() { cout<<"调用析构函数"<<endl; if(_addr!=NULL) delete []_addr; } int main() { char *p = "beijing"; Student stuA(123456,"zhangsan",p); cout<<"stuA:"; stuA.show(); Student stuB(stuA); //使用sheepA初始化新对象sheepB cout<<"stuB:"; stuB.show(); return 0; }
💻第二题：
#include <iostream> using namespace std; class Student { public: Student(string _name,int _score); static float average(); static float total_score; static int count; private: string name; float score; }; Student::Student(string _name,int _score){ name=_name; score=_score; total_score+=score; count++; } float Student::total_score=0.0; int Student::count=0; float Student::average(){ return (total_score/count); } int main() { string name; float score; cout<<"input name,socre:"; cin>>name>>score; Student stu1(name,score); cout<<"input name,socre:"; cin>>name>>score; Student stu2(name,score); cout<<"input name,socre:"; cin>>name>>score; Student stu3(name,score); cout<<"total_socre:"<<Student::total_score<<",average:"<<Student::average()<<endl; return 0; }
💻第三题：
#include <iostream> #include <cmath> using namespace std; class Point { friend float dis(Point &p1,Point &p2); public: Point(float x,float y); ~Point(); private: float _x; float _y; }; Point::Point(float x=0,float y=0):_x(x),_y(y) { cout<<"初始化坐标点"<<endl; } Point::~Point() {} float dis(Point &p1,Point &p2) { float d=sqrt((p1._x-p2._x)*(p1._x-p2._x)+(p1._y-p2._y)*(p1._y-p2._y)); return d; } int main() { Point p1(5,5); Point p2(10,10); float distance=dis(p1,p2); cout<<"两点间距离是:"<<distance<<endl; return 0; }
